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The laser diode is a laser where the active medium is a semiconductor similar to that found in a light-emitting diode. The most common type of laser diode is formed from a p-n junction and powered by injected electric current. The former devices are sometimes referred to as injection laser diodes to distinguish them from optically pumped laser diodes, namely solid state lasers. 1 Applications of High Power Laser Diodes Defense and Security 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. 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. 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.
Laser diodes are used in many significant therapeutic applications. Among the most important are the treatment of cancer by Photo Dynamic Therapy, the treatment of macular degeneration (AMD) and diabetic retinopathy by Photocoagulation and the prevention of secondary dental infection by Photodynamic Disinfection. Other medical applications for laser diodes include early cancer detection by Computed Tomography Laser Mammography and the treatment of Carpal Tunnel Syndrome and musculature strain with the use of Low Level Laser Therapy. Lasers also find cosmetic applications in hair removal. Commercial and Industrial Applications Laser diodes are often used in industrial applications as solid state laser pump sources. They are typically found in the form of diode arrays and high power diode stacks. Laser diodes are popular as:
Solid state laser pump sources, including disc, fiber and YAG lasers.
Direct or fiber coupled applications including plastic welding, micro welding, and soldering.
Materials processing, including micro machining.
Red and Green Lightshows.
TV Displays.
Automotive.
Raman Spectroscopy.
Machine Vision.
Digital Printing Printer manufacturers are constantly innovating to improve their key performance indicators against the backdrop of a highly competitive environment that sees new entrants every year. The underlying technology in digital presses is an electro photographic process. The writing head in most digital presses utilizes lasers and is an important factor in determining the press performance.
Computer to Plate Computer to Plate (CtP) thermal machines expose pre-sensitized plates utilizing digital data and laser writing heads. These machines, available from a wide variety of manufacturers, are generally purchased by commercial color printers for exposing conventional litho printing plates, or by packaging printers for exposing 'Flexo' Plates. These plates are then loaded onto printing presses for printing. Depending on the printer's press size and volume requirements, the CtP devices vary in speed, automation, and format. The market is very competitive, making it essential for CtP manufacturers to innovate constantly, reducing costs and increasing capabilities, particularly productivity. The writing head, which utilizes lasers, plays a key role in determining the productivity, quality, and cost of output.
Laser Coding & Laser Marking
Coding and marking solutions for primary and secondary packaging and labels have been dominated by inkjet and thermal products. These are incorporated into production lines or binderies, taking digital variable data and imaging to substrate. The products to be coded can be static or running on a production line at many meters per second. The information is typically bar coding, date information, product coding, and batch information. Laser coding and laser marking solutions have entered the market bringing new benefits for certain applications. Laser solutions can inherently bring higher reliability, non contact solutions and eliminate consumable costs associated with ink and ribbons.
Across all application areas, increased power, brightness, and reliability are critical to improving laser diode performance. Greater power and brightness per unit price enable the development of more cost-effective solutions and solve a more diverse range of application challenges.
2 Common Wavelengths 375 nm - Excitation of Hoechst stain, Calcium Blue, and other fluorescent dyes in fluorescence microscopy.
405 nm - InGaN blue-violet laser, in Blu-ray Disc and HD DVD drives.
445 nm - InGaN Deep blue laser multimode diode introduced for use in mercury free high brightness data projectors.
473 nm - Bright blue laser pointers, still very expensive, output of DPSS systems.
485 nm - Excitation of GFP and other fluorescent dyes.
510 nm - Green diodes developed by Nichia for laser projectors.
635 nm - AlGaInP better red laser pointers, same power subjectively 5 times as bright as 670 nm one.
640 nm - High brightness red DPSS laser pointers.
657 nm - AlGaInP DVD drives, laser pointers.
670 nm - AlGaInP cheap red laser pointers.
760 nm - AlGaInP gas sensing: O2.
785 nm - GaAlAs Compact Disc drives.
808 nm - GaAlAs pumps in DPSS Nd:YAG lasers.
848 nm - Laser mice.
980 nm - InGaAs pump for optical amplifiers, for Yb:YAG DPSS lasers.
1064 nm - AlGaAs fiber-optic communication, DPSS laser pump frequency.
1310 nm - InGaAsP, InGaAsN fiber-optic communication.
1480 nm - InGaAsP pump for optical amplifiers.
1512 nm - InGaAsP gas sensing: NH3.
1550 nm - InGaAsP, InGaAsNSb fiber-optic communication.
1625 nm - InGaAsP fiber-optic communication, service channel.
1654 nm - InGaAsP gas sensing: CH4.
1877 nm - GaSbAs gas sensing: H2O.
2004 nm - GaSbAs gas sensing: CO2.
2330 nm - GaSbAs gas sensing: CO.
2680 nm - GaSbAs gas sensing: CO2.
Newopto Technology Corporation is a high-tech service company that is specialized in developing and marketing of Lasers, Optical measurement, Spectroscopy instruments and Detectors & Optics, and providing the solutions for specific applications. We are willing to focus on light together with you, and dedicated to promoting the development of the photonics industry in China and worldwide. Supported by Newopto.com |
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