What is the efficiency of semiconductor laser?
Within only a few decades, the semiconductor laser diode has evolved into a family of robust, reliable devices, with individual conversion efficiencies of better than 60 percent, continuous output powers of several kilowatts, modulation rates of several tens of gigahertz, and wavelengths from 0.4 to beyond 2 µm.
Who invented first semiconductor laser?
Nick Holonyak
Jun-ichi Nishizawa
Laser diode/Inventors
In 1962, Robert N. Hall demonstrated the first laser diode device, which was made of gallium arsenide and emitted in the near-infrared band of the spectrum at 850 nm. Later that year, Nick Holonyak, Jr. demonstrated the first semiconductor laser with a visible emission.
When was the semiconductor laser invented?
September 1962
In September 1962 researchers from IBM, independently and almost simultaneously with researchers from General Electric and MIT’s Lincoln Laboratory, demonstrated laser action in the semiconductor gallium arsenide. General Electric researcher Robert Hall developed one of these lasers in 1962.
Does semiconductor laser have high efficiency?
Semiconductor lasers are small, very efficient lasers with dimensions of less than a millimeter (see semiconductor gain media). The wavelengths of commercial lasers range from approximately 600 nm in the red to 1.6 μm in the near infrared.
What does ND YAG mean?
neodymium-doped yttrium aluminium garnet
Nd:YAG (neodymium-doped yttrium aluminium garnet) is a crystal that is used as a laser medium for solid-state lasers.
How the photon energy is released in semiconductor laser?
Light is produced when an electron near the bottom of the conduction band recombines with a hole in the valence band. The photon emitted during this recombination process carries an energy hν ≈ Eg, where Eg is the bandgap energy of the semiconductor.
When was laser first invented?
Every now and then, a scientific breakthrough occurs that has a revolutionary impact on daily life. One example of this is the invention of the laser, which stands for light amplification by stimulated emission of radiation.
Where was laser first used commercially?
The first commercial application of Laser Materials Processing was in May of 1967 when Peter Houldcroft of TWI (The Welding Institute) in Cambridge, England used an oxygen-assisted CO2 laser beam to cut through a sheet of steel 1 mm thick.
What is the main difference between conventional lasers and semiconductor lasers?
In addition, solid-state lasers are always optically pumped, whereas semiconductor lasers are excited by the passage of electric current through them. We have already seen how atomic energy levels become modified when two or more atoms bind to form a molecule.
How does a semiconductor laser different from other laser?
Unlike other lasers, semiconductor laser does not need mirrors to obtain the reflectivity needed to produce feedback mechanism. Reflection from the cleaved ends of the semiconductor chip is enough to produce lasing.
What is the current research and development in semiconductor laser technology?
Semiconductor lasers are the subject of extensive research and development worldwide. It is not possible to summarize all research efforts in semiconductor laser technology here; we do note that the worldwide efforts should improve the performance parameters of commercially available devices in the near future.
What is the lifetime of a semiconductor laser?
But in the hands of an inexperienced operator, the lifetime of a semiconductor laser may be not years, but a few seconds.
What are the applications of semiconductor lasers?
Judged by economic impact, semiconductor lasers have become the most important class of lasers. They are now used in applications such as cable TV signal transmission, telephone and image transmission, computer interconnects and networks, compact disc (CD) players, bar-code readers, laser printers, and many military applications.
How are semiconductor lasers made?
Semiconductor lasers are mass produced by depositing various layers of p- and n-doped materials, insulating material, and metal contact layers by lithographic techniques.