lunes, 15 de febrero de 2010

A laser pointer is a small (usually battery-powered) laserdevice designed for pointing at objects by illuminating them with a collimated visible laser beam. Most laser pointers, particularly the cheap ones, contain a small GaInP/AlGaInPlaser diode operating somewhere in the red spectral region, a collimating lens, a simple electronic diode driver, and a battery compartment for e.g. three coin cells. Some significantly more expensive pointers, as shown in Figure 1, emit green or even blue or yellow light and normally contain a small diode-pumped solid-state laser with a nonlinear crystal for frequency doubling. Green laser pointers are usually based on a miniature Nd:YVO4 laser with a KTP crystal for intracavity frequency doubling. Here, Nd:YVO4 is beneficial for a low threshold pump power, and KTP works in a relatively wide temperature range, thus not requiring means for temperature stabilization.
laser pointer
Figure 1: A green-emitting laser pointer, containing a tiny diode-pumped frequency-doubled solid-state laser. Red laser pointers are available in smaller sizes, because they do not need as large batteries.
Laser pointers should not be confused with lamps containing light-emitting diodes (LEDs), which emit a much more diffuse beam (with much lower spatial coherence, similar to that of an incandescent lamp) and can also emit light with different colors, or white light.


A typical use of a hand-held laser pointer is to point at some screen or chart during a presentation, e.g. a conference talk. This is convenient because it can be done from a large distance and requires only a small hand-held device. However, the visibility of the generated spot on the screen is often poor (particularly forred laser pointers with relatively long emission wavelength), and a fast-moving light spot can have a somewhat nervous appearance. Therefore, some people prefer an old-fashioned telescopic pointing device for presentations.
Laser pointers can be useful for, e.g., aligning some machinery, or for certain optical distance measurements.

Brightness and Color

The apparent brightness of the illuminated spot depends strongly on the wavelength of the emitted light. Most devices operate in the red spectral region, where the sensitivity of the eye rapidly decreases with increasing wavelength. Devices with 650-nm output appear about twice as bright as those emitting the same power at 670 nm, and 635-nm devices still about two times brighter. However, the shorter-wavelength laser pointers are typically more expensive. This is particularly true for green lasers, which are significantly brighter than their red counterparts, but are still expensive. They involve a diode-pumpedsolid-state laser and a frequency doubler. Due to the typically poor conversion efficiency of the frequency doubler at low power levels, hundreds of milliwatts of infrared (typically 1064-nm) light are required for generating a few milliwatts in the green, and the batteries will accordingly not last very long, unless they are comparatively heavy.

Range of a Laser Pointer

Lay persons often ask what is the range of a laser pointer is, and responding to this interest some producers specify some more or less questionable numbers.
If the question is meant to be how far the light of a laser pointer can propagate, the correct answer is that there is no limit, provided that the light is not absorbed or scattered away in the atmosphere. However, the beam area will eventually become larger due to the beam divergence, so that the intensitye.g. on a screen will be reduced even if the overall power remains constant. Accordingly, an airplane pilot looking down into such a beam from an altitude of 10 km will not be disturbed by the remaining small intensity.
The range of a laser pointer may also be understood as the maximum distance from which the spot on the screen can be seen. That kind of range is normally not limited by the beam divergence but by the overall optical power (apart from the wavelength and level of ambient light), since the issue is not the comparatively minor divergence on the way from the laser pointer to the screen, but rather the huge divergence of the scattered light on the way back. Therefore, someone standing next to the illuminated screen would easily see the spot when it is already hardly perceivable from the position of the laser pointer.

Safety Hazards

There have been extensive debates on laser safety issues associated with laser pointers. Typical output powers are a few milliwatts – normally below 5 mW in order to comply with safety class 3R, and sometimes below 1 mW for class 2. Direct staring into a 1-mW beam can be irritating for the eye: it can cause temporary flash blindness. However, nobody would normally do that long enough to cause serious eye damage. Nevertheless, great care should be taken, e.g. when children are playing with laser pointers, if laser pointers are at all considered to be suitable as toys. Significant hazards could arise e.g. if somebody walking down stairs or a car driver is irritated by a laser beam.
There are some reports saying that cheap green laser pointers are sold which do not have a filter to eliminate the infrared light, and therefore can emit hundreds of milliwatts in the infrared spectral region. This is obviously a terrible safety hazard; an eye directly hit by such a beam could be destroyed within a fraction of a second.

Guillermo Alejandro Luque Terán
Comunicaciones de Radio Frecuencia (CRF)

OPTOELECTRONIC APPLICATIONS: Materials Processing - Diode lasers test their mettle in surface treatment

Most everyone has heard the old adage, "If it ain't broke, don't fix it." But history has repeatedly demonstrated that technology advances can often improve a process or outcome we didn't even realize needed fixing. (Then it's just a matter of waiting until it becomes affordable.)
Advances in high-power diode lasers are a case in point, especially when it comes to materials processing. During the past 20 years, multimode diode-laser bars and individual single-emitter diode devices have achieved increasingly higher output powers and better power-conversion efficiencies, allowing semiconductor lasers to evolve from the scientific arena into true industrial tools. In fact, interest in direct-diode materials processing has been a key factor in the development of high-power diode lasers. While diode lasers are still a few years away from being practical ablation or cutting tools for heavy metals, they are gaining traction in materials-processing applications in which beam quality and brightness are not critical to the outcome, such as surface treatment.
Surface treatment is one of the most efficient uses of laser energy and one of the most controllable heating processes when working with metal components. Laser-based techniques such as heat treating, cladding, alloying, and welding have become well-established in the automotive, aerospace, energy, defense, and machine-tool industries for applications ranging from increasing wear resistance of turbine blades to improving corrosion resistance and performance in car engines. Historically, these applications have been served by Nd:YAG and CO2 lasers, both of which are well-accepted materials-processing tools. Displacing these lasers would require a solution that brings not only operational but financial advantages.
This is where high-power diode lasers come in. While engineers continue to work out a few remaining kinks-such as how to offset the thermal issues that arise in a compact package as it churns out 3 to 4 kW of power in a single shot-the diode laser offers a number of advantages for industrial surface-treatment applications as compared to the Nd:YAG or CO2laser. In particular, the shorter wavelength of the diode laser enables much better absorption of the laser energy, leading to an overall lower power requirement for surface treatment applications. A diode-laser cladding system can typically perform cladding with half as much laser power as a CO2 laser (see table). The diode laser typically has 25% to 30% wall-plug efficiency, compared to about 10% for the CO2 and the Nd:YAG laser. In addition, the diode laser can be fiber-delivered, which makes it more attractive for automated applications. Also, there is no need to precoat the metal to increase absorption-a necessity with the CO2.

Electrical energy costs
CO2Nd:YAG (diode pumped)Diode
Required laser power5 kW3 kW3 kW
Average wall-plug efficiency10%10%30%
Approximate electrical power consumption of the lasers50 kW30 kW10 kW
Electrical power cost per hour @0.09$/kWh4.50 $/h2.70 $/h0.90 $/h
Source: Fraunhofer
"Most laser-cladding operations use the CO2 laser, but there are inherent disadvantages compared to the diode laser or other lasers with the same wavelength as the diode," said Eric Stiles, laser-division manager at the Fraunhofer Center for Coatings and Laser Applications (Plymouth, MI). "But the diode laser is interesting for applications like cladding because of the low cost for kilowatt power. A 3 to 4 kW diode-laser system can do the same work as a 6 to 8 kW CO2-laser system because a lot of the energy of the CO2 is lost. With the diode you get much better absorption with a lot of materials, especially at lower power intensities where CO2 absorption is poor."

Pros and cons

Despite these advantages, however, diode lasers still need further refinement in terms of being reliable enough for intensive industrial applications like laser cladding, a process in which laser energy is used to melt or weld a metallic or ceramic powder onto a substrate to create a wear- or corrosion-resistant layer on a metal component (see Fig. 1). While the current generation of high-power diode lasers has resolved many of the reliability issues that plagued earlier generations, random failures remain a problem when a diode-laser system is used in high-volume production applications, particularly when pulsing is required. Thus, while the overall cost of an industrial diode-laser system should be lower, the need to replace the diodes more frequently disrupts production cycles and increases overall cost of ownership.
"The main specificity of this market [materials processing] is the operating regime," Franck Leibreich, director of marketing at Newport's Spectra-Physics Lasers Division (Mountain View, CA). "Long micropulses-one second on, one second off-is the most difficult operating regime for the diode because it stresses the diode very much, which leads to random failures. So we and others are working to make the lasers more robust by focusing on the interaction between the soldering material and the heat sink in order to compensate for the coefficient of expansions. The goal is to optimize the thermal exchange between the materials."
Brightness is another factor. According to Leibreich, the need to transform inherently low-brightness, highly asymmetric diode lasers has led to the development of several important beam-shaping and beam-combining technologies ( As a result, diode-laser devices that produce 4 kW from a 600-µm-diameter-core fiber are now being used in applications such as cladding and annealing.
"As diode lasers continue to evolve, we can predict that there are two areas where this technology will grow in attraction for industrial applications," said Phillip Anthony, manager, macro business unit at Rofin-Sinar (Plymouth, MI). "The life of the diodes and diode bars will get longer, and as this happens the long-term cost of ownership becomes less of an issue. Second, a lot of time and energy is being spent on improving the beam quality, which should lead to becoming more realistic for fiber delivery. In the end this will be driven by the cost of ownership and the predictable life of the diode that can be measured in tens of thousands of hours."

The real world

While efforts are under way to improve the reliability and lifetimes of diode lasers, some companies and organizations are already demonstrating the efficacy of this technology for surface treatment. At Fraunhofer, for example, Stiles and his colleagues have developed a new cladding process that utilizes a 3 kW Rofin-Sinar direct diode laser and a coaxial powder-feeding nozzle. It was initially tested in the oil industry, in which new wear-protective hard coatings were developed, tested, and applied to a number of down-hole drilling tools.
On the commercial front, Nuvonyx (Bridgeton, MO) and Laserline (Mülheim-Kärlich, Germany) have both had some success with their diode-laser cladding systems (see Fig. 2). Nuvonyx, founded in 1998 by former employees from the McDonnell/Douglas Laser Systems Division, has been a pioneer in the commercial introduction of high-power direct-diode and fiber-coupled laser systems for industrial applications in aerospace and defense. In 2005 Nuvonyx was acquired by ICx Technologies, which then acquired Thales Laser Diode (Orsay, France), which has since become Nuvonyx Europe. The company's newest product, introduced in June 2006, is a fiber-coupled diode-laser system with an optical power density of more than 1 MW/cm², which the company says is an order of magnitude higher than any other commercially available system operating at a single wavelength.  

Laserline's expertise is also in fiber-delivered high-power diode lasers up to 6 kW. According to Klaus Kleine, vice president of U.S. operations, Laserline is beginning to see diode-laser cladding systems replacing CO2 and Nd:YAG lasers in industrial applications, particularly in the United States. While the aerospace and power-plant industries continue to account for the bulk of laser-cladding applications, Kleine says there is a big push under way in other industries and that the compactness, efficiency, and affordability of the diode-laser systems should begin to attract more customers.

"The automotive applications are much more prevalent in Europe, which is also at the forefront of installed diode-laser systems for surface treatment," he said. "A lot of these advances are being pushed by diesel-engine technology; the goal (in Europe) is to make diesel engines cleaner and much more fuel efficient via surface treatment."

Guillermo Alejandro Luque Terán
Comunicaciones de Radio Frecuencia (CRF)

domingo, 14 de febrero de 2010

Terms Describing Laser Diode Absolute Maximum Ratings

Terms Describing Laser Diode Absolute Maximum Ratings:
Commonly used abbreviations are shown in parenthesis.
Case Temperature (Tc) – Device temperature measured at the base of the package. 
Operating Temperature (Topr) – Range of case temperatures within which the device may be safely operated.
Optical Power Output (Po) – Maximum allowable instantaneous optical power output in either continuous (CW) or pulse operation. Up to this point, there are no kinks in the optical power output vs. forward current curve.

Important note: The optical power output specification is applicable to the bare laser diode – it does not allow for, or take into consideration, any optics that may be in the optical path, such as a collimating lens located between the laser diode and a power meter or other detector.

Caution: Do not exceed the specified optical power output -- even an instantaneous (less than a nanosecond) application of excessive current or voltage may cause deterioration or catastrophic optical damage (COD) to the facets. 
Reverse Voltage (VR) – Maximum allowable voltage when reverse bias is applied to the laser diode or photodiode. For laser diodes with an internal monitor photodiode, the reverse voltage is specified for the laser diode as VR (LD) and for the photodiode as VR (PD)
Storage Temperature (Tstg) – Range of case temperatures within which the device may be safely stored. 

Terms Describing Laser Diode Electro-optical Characteristics:
Commonly used abbreviations are shown in parenthesis.
Automatic Power Control (APC) – Laser diode drive circuit based on a photodiode feedback loop that monitors the optical output and provides a control signal for the laser diode which maintains the operation at a constant optical output level. See additional information below on Drive Circuits and Operating in Constant Power Mode vs. Constant Current Mode.
Automatic Current Control (ACC) or Constant Current – Laser diode drive circuit that operates the laser diode without a photodiode feedback loop, the laser diode is simply driven at constant current. The optical output will fluctuate as the laser diode temperature changes. See additional information below on Drive Circuits and Operating in Constant Power Mode vs. Constant Current Mode.
Fall Time – Time required for the optical output to fall from 90% to 10% of its maximum value.
Mode Hopping – As the temperature of the laser chip increases, the operating wavelength also increases. Rather than a smooth, continuous transition in the operating wavelength, the wavelength makes discrete jumps to the longer wavelength modes. The phenomenon is referred to as "mode hopping" or "mode jumps".
Monitor Current (Im) – The current through the photodiode, at a specified reverse bias voltage, when the laser diode is producing its typical optical power output. Note: The manufacturers data may list specifications based on operation at lower optical output power than the devices absolute maximum rating. For example, the test condition might be 20mW for a diode with an absolute maximum optical output of 30mW.
Operating Current (Iop) – The amount of forward current through the laser diode necessary to produce the specified typical optical output at a specified operating temperature. 
Operating Voltage (Vop) – The forward voltage across the laser diode when the device produces its specified typical optical output at a specified operating temperature. 
Photodiode Dark Current (ID(PD)) – The current through the reverse biased internal monitor photodiode when the laser diode is not emitting.
Positional Accuracy (Dx, Dy, Dz) – Also referred to as emission point accuracy. These specifications define the positional accuracy of the laser diode emitter with respect to the device package. Delta x and delta y are measured as the planer displacement of the chip from the physical axis of the package. Delta z is measured perpendicular to the reference surface. Specifications may list both angular error expressed in degrees and the linear error in microns.  
Rise Time – Time required for the optical output to rise from 10% to 90% of its maximum value.
Slope Efficiency (SE) or (h) – Also referred to as differential efficiency. This is the mean value of the incremental change in optical power for an incremental change in forward current when the device is operating in the lasing region of the optical power output vs. forward current curve. 
Threshold Current (Ith) – The boundary between spontaneous emission and the stimulated emission shown on the optical power output vs. forward current curve. Below the threshold current point, the output resembles the incoherent output from a LED; at or above the specified threshold current, the device begins to produce laser output. Once past the threshold point, stimulated emission is achieved and the optical output increases significantly for a small increase in forward current.
Wavelength (lp) – The wavelength of light emitted by the laser diode. For a single mode device, this is the wavelength of the single spectral line of the laser output. For a multi-mode device, this is the wavelength of the spectral line with the greatest intensity.

Top of Page

Terms Describing Laser Diode Optical Characteristics:

Commonly used abbreviations are shown in parenthesis.
Aspect Ratio (AR) – The ratio of the laser diode's divergence angles, q^ (perpendicular) and q// (parallel). A diode with a 27º perpendicular divergence and a 9º parallel divergence has an elliptical beam with an aspect ratio of 3:1. Please refer to the
laser diode mounting kit page to see the difference between a nearly circular beam and the typical elliptical beam.
Astigmatism (As) or (DAs) – The laser beam appears to have different source points for the directions perpendicular and parallel to the junction plane. The astigmatic distance is defined as the distance between the two apparent sources. A laser diode with a large amount of astigmatism must have the astigmatism corrected  (or reduced) if the laser diode output is to be accurately focused – otherwise, the resulting focused beam will be astigmatic.
Beam Divergence (q^) and (q//) – Also referred to as radiation angles. The beam divergence is measured as the full angle and at the half-maximum intensity point, known as Full Width Half Maximum or FWHM. Angular specifications are provided for both the perpendicular axis and parallel axis.
Coupling Efficiency – The beam from the laser diode diverges as defined by the beam divergence specification. In coupling the laser diodes widely divergent beam into a lens or other device such as a fiber, the result is typically less than 100%. Coupling efficiency is defined as the percentage of total power output from the laser which effectively enters the external device (i.e. a lens or fiber).
Far Field Pattern (FFP) – Intensity profile of the beam when measured at a distance from the front facet of the laser diode chip.
Multimode Diodes – Laser diodes have either single or multiple longitudinal modes. For a multimode laser diode the emission spectrum consists of several individual spectral lines with a dominant line (line with the greatest intensity) occurring at the nominal wavelength of the device. Multimode laser diodes are often desirable as problems with mode hops are suppressed – consequently, multimode diodes generally have a better signal-to-noise ratio.
Near Field Pattern (NFP) – Intensity profile of the beam when measured at the front facet of the laser diode chip.
Numerical Aperture (NA) – The numerical aperture describes the ability of a lens to collect light from a source placed at its focal point. The maximum acceptance angle q, is measured from the center axis of the cone of light to the outside or surface of the cone.
Polarization Ratio – The output from a single cavity laser diode is linearly polarized parallel to the laser junction. Spontaneous emission with a random polarization and/or with a polarization perpendicular to the laser junction is also present. The polarization ratio is defined as the parallel component divided by the perpendicular component. For a diode operating near its maximum power the ratio is typically greater than 100:1. When operating near the threshold point, the ratio would be considerably lower as the spontaneous emission becomes more significant. 
Single-mode Diodes – Laser diodes have either single or multiple longitudinal modes. For a single-mode laser diode the emission spectrum consists of a single spectral line occurring at the nominal wavelength of the device. At output levels near threshold, multiple spectral lines may be present in the emission spectrum however, these secondary lines decrease as the output increases.

Top of Page

FAQ's and Laser Diode Basics:
There are a number of precautions listed in the laser diode manufacturer's catalogs that should be observed when working with laser diodes. Below are a few points that might be helpful if you're new to this field:
Safety Considerations – The laser beam emitted by the laser diode is harmful if aimed directly into the human eye. Never look directly into the laser beam or at any specular reflections of the laser beam.
Electro-Static Discharge – Laser diodes are extremely sensitive devices and visible laser diodes (VLD's) tend to be the most sensitive type. The handling precautions outlined by the laser diode manufacturers are not overstated – good work habits require personal grounding straps and grounded equipment. ESD does damage laser diodes!
Drive Circuits – Laser diodes should always be driven by either a Constant Current or Automatic Power Control (APC) circuit (the APC circuit may also be referred to as a Constant Power Mode circuit). For simplicity, an APC circuit is generally preferred, especially if the ambient temperature fluctuates. Typical circuits include slow-start or soft-start circuitry and provisions to ensure that spikes, surges, and other switching transients are eliminated. Regardless of type of circuit used, the drive current must not overshoot the maximum operating level - exceeding the maximum optical output for even a nanosecond will damage the mirror coatings on the laser diode end facets.

A standard laboratory power supply is not suitable for driving a laser diode.

Examples of the recommended drive circuits can be found in most manufacturer's laser diode data books. Unless you have prior experience with laser diodes and/or their drive circuits, this is not a place to reinvent the wheel - it can be very frustrating and expensive.
Operating in Constant Power Mode vs. Constant Current Mode – The characteristics of a laser diode are highly dependent on the temperature of the laser chip. For instance, the wavelength of a typical GaAlAs diode will increase on the order of 0.25nm for a 1°C rise in temperature. With a single mode diode, the change in wavelength may produce an undesirable effect known as "mode hops or mode-hopping".
Other characteristics directly related to laser diode's operating temperature are; threshold current, slope efficiency, wavelength, and lifetime.  Perhaps the most important characteristic is the effect of temperature on the relationship between the diode's optical output and the injection current. In this case, the optical output decreases as the operating temperature increases or, conversely the optical output increases as the operating temperature decreases. Without limits and safeguards built into the laser drive circuit, a wide swing in operating temperature could be catastrophic. However, there are two techniques commonly used to achieve a stable optical output from a laser diode:
Constant Current mode combined with precise control of the diode's operating temperature is generally the preferred operating method. The constant current mode provides a faster control loop and a precision current reference for accurately monitoring the laser current. Further, in many cases the laser diode's internal photodiode may exhibit drift and have poor noise characteristics. If performance of the internal photodiode is inferior, the diode's optical output is likely to be noisy and unstable as well.
Constant Current operation without temperature control is generally not desirable – if the operating temperature of the laser diode decreases significantly, the optical power output will increase and could easily exceed the absolute maximum.
Constant Power or APC mode precludes the possibility of the optical power output increasing as the laser diode's temperature decreases. However, when operating in the constant power mode and without temperature control, mode hops and changes in wavelength will still occur. Further, if the diode's heat sink is inadequate and the temperature is allowed to increase, the optical power will decrease.  In turn, the drive circuit will increase the injection current, attempting to maintain the optical power at a constant level. Without an absolute current limit thermal runaway is possible and the laser may be damaged and/or destroyed.
Summary – for stable operation and maximum laser lifetime – temperature control and constant current operation is generally the best solution. However, if precise temperature control of the laser diode is not practical, then an APC circuit should be used.
Drive Circuit Precautions – Even when a laser diode is driven by a suitable drive circuit, watch for possible intermittent or unreliable connections between the laser diode and the drive circuit. An intermittent contact in the photodiode feedback circuit will very likely destroy the laser diode. One not-so-obvious component to consider is the power control. If a potentiometer is used for setting the laser diode's power, evaluate the circuit design to determine the failure mode if the potentiometer's wiper breaks contact with the resistive element. Also, never use a switch or relay to make or break the connection between the drive circuit and the laser diode.
Power Measurements – The output from a laser diode must be measured with an optical power meter or a calibrated, large area photodiode. It's not practical or safe to estimate a laser diode's output power based on the diode manufacturers minimum-maximum data as each diode has unique operating characteristics and manufacturing tolerances.

Remember, once the laser diode is past the threshold point, stimulated emission is achieved and the optical output increases significantly for a small increase in forward current. Therefore, a very slight increase in drive current may cause the optical output to exceed the absolute maximum. Even with a visible diode, it's not feasible to judge the laser output by eye, an optical power meter or calibrated photodetector must be used.

Also, be sure to include optical losses through any lenses or other components when making measurements or calculations.
Operating Temperature and Heat Sinks – In most applications, laser diodes require heat sinks especially when operated continuously (CW). Without a heat sink the laser diode junction temperature will quickly increase causing the optical output to degrade. If the laser diode temperature continues to rise, exceeding the maximum operating temperature, the diode can be catastrophically damaged or the long term performance may degrade significantly. Generally, a lower operating temperature will help extend the diode's lifetime as the laser diode's reliability and MTTF are directly related to the junction temperature during operation. VLD's with lower wavelengths, i.e. ~635nm, appear to be more sensitive to temperature and users might consider thermoelectric cooling if operating in an environment with elevated ambient temperatures or if operational stability is a prerequisite. Also, using a small amount of a non-silicone type heat sink compound will improve thermal conductivity between the diode and heat sink.
Lifetime note: If the laser diode's operating temperature is reduced by about 10 degrees, the lifetime will statistically double.
Windows – Keep the laser diode window, and any other optics in the path, clean. Dust or fingerprints will cause diffraction or interference in the laser output that can result in lower output or anomalies in the far-field pattern. The window should be cleaned using a cotton swab and ethanol when necessary.
Cyanoacrylate Adhesive Precaution – "Super glue" should not be used anywhere near laser diodes - or near any other optical component - outgassing may fog windows and other optical surfaces. The amount of fogging, or the time required to observe the fogging, varies with different products. If you're in doubt, test the adhesive over time at an elevated temperature and in a sealed container. For example, place a drop of the adhesive in question on a piece of glass, something like a microscope slide, then place the sample in a plastic bag and seal the bag.

Top of Page

Important Notice to Purchaser:

All statements, technical information and recommendations related to Optima's products are based on information we believe to be reliable, but the accuracy or completeness thereof is not guaranteed, and the following is made in lieu of all warranties expressed or implied:
Seller's and manufacturer's only obligation shall be to replace such quantity of the product proved to be defective. Neither seller nor manufacturer shall be liable for any injury, loss or damage, direct or consequential, arising out of the use or the inability to use the product. Before utilizing the product, the user should determine the suitability of the product for its intended use. The user assumes all risk and liability whatsoever in connection with such use.
No statement or recommendation not contained herein shall have any force or effect unless in written agreement signed by officers of the seller and manufacturer. 
Anderson Jose Mariño Ortega

Laser Diodes for Defense Applications

Laser Diodes for Defense Applications
Traditionally the defense and aerospace industries have used laser diodes as pump sources for solid-state systems
Traditionally the defense and aerospace industries have used laser diodes as pump sources for solid-state systems. This continues to be the largest application for laser diodes with the typical format being laser diode arrays and high power laser diode bars. Laser diodes are popular as:
•Pump sources for solid state lasers, including disc, fiber, and YAG lasers
•Rangefinding (TOF)
•Illuminators / Designators
•Weapons Simulation (MILES)
•Ordinance Initiation (Fuzes) at 810nm to 980nm
•Active Optical Target Detectors
The increasing need for high performing solutions operating best-in-class technologies is driving demand for laser diode technology throughout the market.

In defense and law enforcement, for example, low power rangefinders (i.e. short-range <10km) utilize laser diodes with single emitters. Target designation at long range requires higher power and brightness, and typically uses laser diode bars and, in some cases, arrays. The highest performance target designation and illumination products use arrays of laser diode bars that produce power in the kilowatt range.
Regardless of the application, in order to improve the performance of laser diodes, both in terms of cost and efficiency, increased power and brightness are key. Greater power and brightness per unit cost enable more cost effective solutions and allow more diverse application of lasers to solve demanding challenges.
Intense manufactures a highly competitive range of high power laser diodes that are ideal for use in aerospace and defense applications. Intense's compact, modular designs and advanced Quantum Well Intermixing (QWI) process deliver laser diodes with high reliability, superior brightness, and enhanced power levels. In addition, Intense supplies INSlam™, monolithic single mode arrays for precise delivery and control of optical energy.
High Power Visible Products
High power, high brightness laser diode components, modules, and systems for the visible spectrum.

High Power Infra-Red Products
High power, high brightness laser diode components and modules for the infrared spectrum.

High Power Bars & Stacked Arrays
High brightness, high optical conversion efficiency, QCW, bars and stacked laser arrays

High Power Individually Addressable Arrays
Individually addressable array and super-array modules with high quality optical output.
Anderson JOse Mariño Ortega
C.I. 17.456.750

Fabrication of first 337 nm laser diodes for biological applications

EPSRC Reference: EP/F033826/1
Title: Fabrication of first 337 nm laser diodes for biological applications
Principal Investigator: Professor M Kuball
Department: Physics
Organisation: University of Bristol
Scheme: Standard Research
Starts: 01 May 2008 Ends: 30 November 2009 Value (£): 16,535
EPSRC Research Topic Classifications:
Functional Ceramics and Inorganics: Characterisation Functional Ceramics and Inorganics: Synthesis and Growth
EPSRC Industrial Sector Classifications:
Aerospace, Defence and Marine
Related Grants:
Recently, with the unfortunate emergence of bio-terrorism and its threat to both military targets and civilian populations, it is necessary to develop a portable and cheap system to continuously monitor for any potential aerosolized agents (biological particles) released from deadly biological weapons in any open area, even in harsh environments. As most bio-molecules show strong absorption in the ultra-violet (UV) spectral region ranging from 280 to 340 nm, an efficient UV lighting source is expected to be a crucial component for next-generation biological detection, biological imaging and disease analysis applications. In particular use of UV laser diodes would enable high sensitivity detection systems.
III-nitride semiconductors are the best materials to make such laser diodes. In last decade, there have been major achievements in this area. However, the achievements are limited to the violet/blue spectral region, with those devices mainly based on the InGaN alloy. Due to a number of challenges in material growth, a 343 nm laser diode is the shortest one so far reported. Obviously, such a laser diode is not short enough to be employable for above applications.
Target of this exploratory project is the development of the first 337 nm UV laser diode based on the GaN/AlGaN material system to replace currently used N2 gas-based lasers. This work is based on recent major advances of the here involved UK teams in the field of III-nitride semiconductors. Further applications of the technology involve biological imaging as an efficient method to detect diseases in a human body, for example, cancerous tissues.
Anderson Jose Mariño Ortega
C.I. 17.456.750

Maquina de soldadura de plastico por laser de diodo

Plastic Welding
Tremendous lifetime with an MTBF of 20.000 hrs
- Air cooled
- High accuracy
- Vibration-free and clean process
- No contact
- No consumables
- No tool wear
Laser systems from Lasea are especially designed for a quick and easy integration into customer specific environments.
Benefit from our many years of experience in customized laser solutions for the industry. We deliver fast, flexible, and reliable systems for your application.
The laser sources integrated in the DL systems are maintenance-free fiber coupled laser diodes. They deliver a high power laser beam at a wavelength chosen between 808nm, 915nm, 940nm, 980nm, and 1.064nm. Their high density beam can weld almost every types of thermoplastics.
The DL electronic offers high accuracy and current stability, an excellent dynamic performance, a high output impedance and low electromagnetic interference. No current overshoots or ringing arise in the laser diode when altering output current or load impedance abruptly.
Different from a conventional laser driver, the DL response in this case is absolutely reliable.
Anderson Jose Mariño Ortega
C.I. 17.456.750

ZL40514 PRODUCT PROFILE 4 Channel, Dual Output CD and DVD Laser Diode Driver with LVDS control signals

The ZL40514 is a high performance laser driver capable of driving two separate cathode grounded laser diodes (e.g. 650 nm and 780 nm laser diodes). The ZL40514 contains a 150 mA low noise read channel (ChR), and three 500 mA LVDS controlled write channels (Ch2, Ch3 and Ch4). The Read channel amplifies the positive current supplied at its reference input, INR, by a fixed factor of 100. Write channels amplify the positive currents supplied at its reference input IN2, IN3, and IN4 by a fixed factor of 240. An on-chip RF oscillator is provided for the reduction of laser mode hopping noise.

Simplified Block Diagram

Features & Benefits

  • Single 5 V supply (±10%)

  • 150 mA low noise read channel with 100 x current gain

  • Three 500 mA write channels with 240 x gain

  • Combined channel output 700mA

  • LVDS control signals

  • Dual output for CD/DVD laser

  • Rise and fall times 0.9 ns typical

  • RF Oscillator, 250-500 MHz (±15%), 100 mA with external resistor control of frequency and amplitude

  • Power Up/Down control

  • > 2 kV ESD

  • Low Rth 24-pin QFN package

  • Contact Zarlink for available Custom Gain and Input Impedance options

  • Related Products

    Part Number Description
    ZL40515 4 Channel, Dual Output CD and DVD Laser Diode Driver with CMOS control signals
    ZL40511 4 Channel, Dual Output CD and DVD Laser Diode Driver with CMOS control signals
    4 Channel, Dual Output CD and DVD Laser Diode Driver with LVDS control signals


    Product Previews

    Typical Applications

    • DVD ±RW/RAM
    • DVD ±R
    • CD-RW
    • CD-R
    • Write optical drives
    • Laser Diode current switch
    • Supports double density DVD

    Packaging Information

    Technical Support

      Anderson Jose Mariño Ortega
      C.I. 17.456.750

    sanyo laser diodes

    Diodos láser azul-violeta de 405 nm de Sanyo (láser azul)
     Diodos de láser azul
    Los diodos láser azul-violeta de 405 nm de Sanyo aportan una potencia de salida de 7 a 85 mW y cuentan con un encapsulado de reducidas dimensiones (5,6 mm), producen un haz con estructura extremadamente estable y con bajo nivel de ruido utilizando implantación iónica y proporcionan no sólo bajo nivel de ruido sino también bajo consumo de corriente y un rendimiento mucho más alto que los diodos láser azul-violeta convencionales.

    Su producción en masa es sencilla, ya que la estructura estable del haz reduce el número de pasos de fabricación y la estructura de los electrodos superior e inferior reducen el tamaño del chip.

    El nuevo diodo láser de Sanyo DL-5146-152 de 405 nm, con 35 mW de onda continua (pulsado con 50 mW) incorpora un fotodiodo monitor interno que se puede utilizar para estabilizar y controlar la potencia óptica de salida con precisión.
    Es ideal para aplicaciones en las que es de vital importancia contar con una salida estable, precisa y controlada como, por ejemplo, en instrumentación biomédica, formación de imágenes médicas, detección por fluorescencia, espectroscopia y microscopía.
    •Almacenamiento óptico de datos de gran capacidad: DVD avanzado
    •Impresión de muy alta resolución
    •Instrumentación biomédica
    •Formación de imágenes médicas
    •Inspección industrial
    Diodos de láser visible de SANYO de 635 - 670 nm
     Sanyo visible láser diodes

    Photonic Products Ltd, authorised distributor of SANYO laser diodes, has announced that SANYO will end production of its industrial red and infrared laser diodes at the end of September 30th 2010. The last time buy date for all affected product lines will be March 31st 2010 - read more

    SANYO ofrece diodos de láser rojo de AlGalnP con estructura de pozos cuánticos múltiples (MQW) en un rango de longitud de onda de 635 a 670 nm, con potencia de salida de 80 mW.
    Los diodos de láser rojo de SANYO se encuentran disponibles con encapsulados de 5,6 mm con configuración de patillas de tipo N, M o P.
    All SANYO laser diodes are lead (pb) free in compliance with the RoHS Directive.
    Diodos láser de SANYO de 405 nm - 830 nm:
    Diodos infrarrojos de 785 nm
    Diodos infrarrojos de 808 nm
    Diodos infrarrojos de 830 nm
    Diodos azul-violeta de 405 nm
    Diodos láser infrarrojos de SANYO de 782 - 830 nm
     Sanyo infrared láser diodes
    Photonic Products Ltd, authorised distributor of SANYO laser diodes, has announced that SANYO will end production of its industrial red and infrared laser diodes at the end of September 30th 2010. The last time buy date for all affected product lines will be March 31st 2010 - read more

    Disponemos de diodos láser infrarrojos de GaAIAs de SANYO guiados por índice y con estructura de pozos cuánticos múltiples (MQW), con bajas corrientes de umbral en el intervalo de longitudes de onda infrarroja (invisible) entre 782 y 830 nm y con potencia de salida de 200 mW.
    Los diodos láser infrarrojos de SANYO están disponibles en encapsulados de 5,6 mm y cubierta cuadrada con configuración de patillas de tipo N, M y P.
    Diodos láser de SANYO de 405 nm - 670 nm:
    Diodos láser azul-violeta de 405 nm
    Diodos rojos de 635 nm   Diodos rojos de 650 nm
    Diodos rojos de 658 nm   Diodos rojos de 670 nm

    Anderson Jose Mariño Ortega
    C.I. 17.456.750

    Diodo Láser compacto más avanzado del mercado

    Diodo láser ultra compacto iBeam smart       

    Toptica Photonics ha presentado en la feria congreso Laser World of Photonics,  que ha tenido lugar en Munich, el diodo láser compacto más avanzado del mercado. Con sus prestaciones innovadoras el iBeam smart permite a los usuarios aumentar la productividad y fiabilidad en sus aplicaciones, al mismo tiempo que optimiza el peso y dimensiones de sus sistemas.

    El iBeam smart representa la primera solución en una caja en módulos de diodo láser compactos. Mide sólo 100 mm x 40 mm x 40 mm y es capaz de mejorar la casi totalidad de aplicaciones de diodos láser existentes. Esto ha sido posible gracias a una alta integración de electrónica basada en microprocesador en combinación con un sobresaliente diseño de óptica mecánica.
    El controlador láser integrado permite al iBeam smart no sólo ser una solución altamente compacta sino también potente, por ejemplo, proporciona 150 mW en operación monomodo a 660 nm.
    Incluso, con este nuevo láser  pueden llevarse a cabo procedimientos de modulación analógica rápida y compleja,  y por supuesto la característica TOP de Toptica el Feedback Induced Noise Eraser (FINE),  incluida como una función estándar en el iBeam smart.
    Especificaciones principales del iBeam smart:
    - Los más altos niveles de potencia alcanzados con diodos láser compactos: 120 mW a 405 nm, 50 mW a 445 nm, 30 mW a 488 nm, 100 mW a 640 nm, 150 mW  a 642 nm y 150 mW a 660 nm.
    - Verdadera solución en una caja (100 x 40 x 40 mm) con un controlador láser integrado.
    - Sólido contra retroalimentación óptica vía FINE.
    - Diámetro de haz de aproximadamente 1,1 mm 1/e2.
    - Excelente calidad de haz y el ruido más bajo de la industria (menos del 0,2%, 
    10 MHz).
    Algunas de las aplicaciones del iBeam smart: microlitografía, exploración de retina, angiografía por fluorescencia, microscopia confocal, citometría de flujo.
    Anderson Jose Mariño Ortega 
    C.I. 17.456.750

    Diodo Laser Aplicaciones

    ¿En qué consiste el láser de Diodo?
    El láser de Diodo  (800 NM de longitud de onda) irrumpe en el mercado de la depilación láser en 1998 como una nueva alternativa terapéutica con utilidades diferenciales frente a las herramientas que existían previamente, con mejoras fundamentadas como el tipo de longitud de onda de emisión, el tamaño del spot, la posibilidad de trabajar a mayor velocidad y la posibilidad de trabajar a pulsos más largos.
    Todas estas características redundan en una mayor protección para la piel de los pacientes de piel oscura o bronceada y la posibilidad de alcanzar mayor profundidad en la piel para alcanzar pelos más profundos.
    ¿Cuáles son las limitaciones del láser de Diodo?
    Es difícil eliminar el pelo rubio
    A 800 Nm de longitud de onda, el coeficiente de absorción del láser de diodo para depilación láser es menor que para la luz del láser de alejandrita a 755 Nm y por lo tanto es necesario trabajar exclusivamente en pelo grueso o mediano y marcadamente cargado de eumelanina o melanina oscura, pues es un equipo sensiblemente menos eficaz en la depilación del pelo de fino calibre (30 micras) o rubio (pigmentado con feomelanina).
    ¿Cuales son las ventajas del diodo laser?
    La posibilidad de ganar en mayor profundidad en la piel gracias a la aplicación del chill tip, pieza de mano por donde se emite la luz, constituida por una punta de zafiro refrigerada a 4ºC gracias a un circuito interno de agua que mantiene la pieza fría. Apretando la pieza de mano sobre la piel en depilación láser, este equipo permite:
    •Enfriar la piel y ganar así en seguridad evitando el riesgo de quemadura epidérmica.
    •Desplazar a otros cromóforos que pudieran competir en la absorción por la emisión láser como la hemoglobina de la sangre circulante
    •Afinar por presión la dermis y acercar al punto de emisión de la luz el target u objetivo de la depilación láser que es el tallo piloso, el epitelio matricial que rodea el área del bulbo piloso y las células madre pluripotenciales que pueblan la protuberancia y que son responsables de la entrada del pelo de nuevo en fase anagen o productora de tallo piloso.

    ¿Cuál es el mecanismo de acción del láser Diodo?

    El mecanismo de acción de este láser de depilación conocido como láser de diodo es el mismo: Fototermolisis selectiva, gracias a la capacidad de la melanina presente en el tallo piloso y en el folículo del pelo que deseamos eliminar con láser, de absorber la emisión de la lúz láser, comportándose así como un cromóforo diana que se calienta al absorber la emisión láser y destruye así la matriz y las células protuberanciales, obteniéndose una depilación láser definitiva.
    Hay que destacar que la epidermis también tiene melanina y es importante neutralizar la absorción que pudiera hacer de la luz la melanina epidérmica para evitar quemaduras superficiales.
    Por ello es imprescindible que la piel del paciente esté lo menos bronceada posible, para tener la seguridad absoluta de que no existirá absorción del láser por parte de la piel de fototipo alto o recientemente pigmentada.
    ¿Para qué tipo de piel está indicado el láser de Diodo?

    El láser de diodo es un tipo de láser para depilación que puede usarse en cualquier tipo de piel desde las más morenas hasta las más claras, así como prácticamente en cualquier área del cuerpo.
    Para cualquier tratamiento de depilación láser es importante cuidarse del sol para evitar los efectos secundarios asegurándonos de no haber tomado el sol durante un mes previo a la realización de cada sesión.
    Algunos equipos para depilacion laser:
    Láser Diodo Mythos

     Características Técnicas:
    - Emisión láser a 810 Nm
    - Capacidad de programación en función del fototipo de piel
    - Pulso doble (Optipulse)
    •Depilación corporal de hombre o mujer
    •Pelo grueso y oscuro
    •Pelo profundo
    •Pieles Fototipos IV y V

    Láser Diodo Mythos
    Láser Diodo Soprano

     Características Técnicas:
    - Emisión de luz láser diodo 800-810 Nm
    - Capacidad de trabajo en modo convencional
    - Capacidad de trabajo en SHR: 10 Hz por segundo
    - Aplicación sobre Tiempo de Daño Térmico y Calentamiento Periférico de las vainas pilosas
    •Además de las indicaciones estándar de un láser de diodo para depilación médica láser Soprano permite trabajar a 10 Hz en barrido obteniéndose un calentamiento gradual de las vainas radiculares del pelo y soslayándose el calentamiento de la superficie cutánea minimizando el riesgo de lesiones en pieles oscuras.
    •Menor dolor.
    •En estudio otras capacidades como su eficacia en pelo claro y fino.

    Láser Diodo Soprano
    Láser Diodo Light Sheer Super Long Pulse

     Características Técnicas:
    Equipo de máximas prestaciones
    Emisión coherente a 800 Nm. Duranción de pulso 2
    400 ms. Fluencia a 400 ms de 100 julios /cm2.
    Láser de Diodo de Alta Potencia.
    Supera todas las prestaciones de la gama.
    •Para depilación de varón o depilación femenina de pelo grueso y profundo.
    •Equipo de elección el pieles oscuras o bronceadas
    •Excelente nivel de seguridad cutánea en depilación láser
    Láser Diodo Light Sheer Super Long Pulse
    Anderson Jose Mariño Ortega C.I. 17.456.750