Unlike a VCSEL, in which two high-reflecting mirrors are incorporated into the laser structure to form the optical cavity, in a VECSEL one of the two mirrors is external to the diode structure. As a result, the cavity includes a free-space region. A typical distance from the diode to the external mirror would be 1 cm. Several workers demonstrated optically pumped [1] VECSELs, and they continue to be developed for many applications including very high power diode laser sources for use in industrial machining (cutting, punching, etc.) because of their unusually high power (see below) and efficiency when pumped by multi-mode diode laser bars. These lasers are in the process[when?] of challenging conventional high power lasers such as solid state (e.g., Nd:YAG) and carbon dioxide lasers for machining operations.
However, electrically pumped VECSELs (another matter entirely), were the brainchild of Aram Mooradian, an engineer known for fundamental contributions to diode laser linewidth studies, who worked for many years at MIT Lincoln Laboratory in Lexington, Massachusetts. Mooradian formed a company, Novalux, Inc., which was the first to demonstrate VECSELs (which they called "NECSELs").[2] Applications for electrically pumped VECSELs include frequency doubling of near-IR VECSEL emitters to attain compact powerful sources of single-mode blue and green light for projection display purposes.
Semiconductor gainedit
One of the most interesting features of any VECSEL is the thinness of the semiconductor gain region in the direction of propagation, less than 100 nm. In contrast, a conventional in-plane semiconductor laser entails light propagation over distances of from 250 μm upward to 2 mm or longer. The significance of the short propagation distance is that it minimizes the effect of "antiguiding" nonlinearities (the same phenomenon is coincidentally quantified by the linewidth enhancement factor relating to Mooradian's above-mentioned earlier work) in the diode laser gain region. The result is a large-cross-section single-mode optical beam which is not attainable from in-plane (a.k.a. "edge-emitting") diode lasers.
In a VECSEL, the external mirror permits a significantly greater area of the diode to participate in generating light in a single mode, resulting in much higher power than otherwise attainable. Monolithic VCSELs emit powers in the low milliwatt range. By contrast, at the 2004 Optical Society of America "Conference on Lasers and Electro-Optics," held in San Francisco, California, one company (Coherent, Inc.) announced 45 watt continuous wave single-mode emission from an optically pumped VECSEL. Numerous other companies and organizations worldwide have adopted the optically pumped architecture for its simplicity.
Referencesedit
^Calvez, S.; Hastie, J. E.; Guina, M.; Okhotnikov, O. G.; Dawson, M. D. (2009). "Semiconductor disk lasers for the generation of visible and ultraviolet radiation". Laser & Photonics Reviews. 3 (5): 407–434. doi:10.1002/lpor.200810042.
^. Archived from the original on June 16, 2006. Retrieved June 20, 2006.
January 01, 1970
vertical, external, cavity, surface, emitting, laser, vertical, external, cavity, surface, emitting, laser, vecsel, small, semiconductor, laser, similar, vertical, cavity, surface, emitting, laser, vcsel, vecsels, used, primarily, near, infrared, devices, lase. A vertical external cavity surface emitting laser VECSEL is a small semiconductor laser similar to a vertical cavity surface emitting laser VCSEL VECSELs are used primarily as near infrared devices in laser cooling and spectroscopy but have also been explored for applications such as telecommunications Comparisons with VCSELs editUnlike a VCSEL in which two high reflecting mirrors are incorporated into the laser structure to form the optical cavity in a VECSEL one of the two mirrors is external to the diode structure As a result the cavity includes a free space region A typical distance from the diode to the external mirror would be 1 cm Several workers demonstrated optically pumped 1 VECSELs and they continue to be developed for many applications including very high power diode laser sources for use in industrial machining cutting punching etc because of their unusually high power see below and efficiency when pumped by multi mode diode laser bars These lasers are in the process when of challenging conventional high power lasers such as solid state e g Nd YAG and carbon dioxide lasers for machining operations However electrically pumped VECSELs another matter entirely were the brainchild of Aram Mooradian an engineer known for fundamental contributions to diode laser linewidth studies who worked for many years at MIT Lincoln Laboratory in Lexington Massachusetts Mooradian formed a company Novalux Inc which was the first to demonstrate VECSELs which they called NECSELs 2 Applications for electrically pumped VECSELs include frequency doubling of near IR VECSEL emitters to attain compact powerful sources of single mode blue and green light for projection display purposes Semiconductor gain editOne of the most interesting features of any VECSEL is the thinness of the semiconductor gain region in the direction of propagation less than 100 nm In contrast a conventional in plane semiconductor laser entails light propagation over distances of from 250 mm upward to 2 mm or longer The significance of the short propagation distance is that it minimizes the effect of antiguiding nonlinearities the same phenomenon is coincidentally quantified by the linewidth enhancement factor relating to Mooradian s above mentioned earlier work in the diode laser gain region The result is a large cross section single mode optical beam which is not attainable from in plane a k a edge emitting diode lasers In a VECSEL the external mirror permits a significantly greater area of the diode to participate in generating light in a single mode resulting in much higher power than otherwise attainable Monolithic VCSELs emit powers in the low milliwatt range By contrast at the 2004 Optical Society of America Conference on Lasers and Electro Optics held in San Francisco California one company Coherent Inc announced 45 watt continuous wave single mode emission from an optically pumped VECSEL Numerous other companies and organizations worldwide have adopted the optically pumped architecture for its simplicity References edit Calvez S Hastie J E Guina M Okhotnikov O G Dawson M D 2009 Semiconductor disk lasers for the generation of visible and ultraviolet radiation Laser amp Photonics Reviews 3 5 407 434 doi 10 1002 lpor 200810042 Novalux home page Archived from the original on June 16 2006 Retrieved June 20 2006 Retrieved from https en wikipedia org w index php title Vertical external cavity surface emitting laser amp oldid 1193477428, wikipedia, wiki, book, books, library,
