Progress in Antimonide-Based Mid-IR Lasers
- PDF / 979,324 Bytes
- 8 Pages / 414 x 635.4 pts Page_size
- 44 Downloads / 195 Views
Abstract Mid-infrared optically pumped semiconductor lasers (OPSLs) are presently being investigated for a variety of commercial and military applications. Active regions in such optically pumped lasers must meet the dual requirements of high gain and low loss at mid-IR wavelengths, combined with sufficient absorption of the optical pump at shorter wavelengths for efficient power conversion. In this paper we report the successful growth, fabrication, and characterization of high-performance OPSLs that employ novel active regions consisting of combinations of GalnAsSb integrated-absorber layers with type-II GaInSb/InAs quantum well regions. With 1.85-pm optical pumping at 85 K, OPSLs with such active regions have exhibited a peak output power of 2.1 W at 3.9 pm, improved beam quality, power conversion efficiency of -8%, and characteristic temperatures of - 47 K.
Introduction There is significant interest in extending the maximum operating wavelength of highpower, room-temperature semiconductor lasers further into the 2-5-/an mid-IR region. At the present time, a number of groups have successfully demonstrated room temperature, CW, wattclass diode lasers which operate near - 2 pm, but it has not yet been possible to achieve such high performance for diode lasers which operate near - 4 pm. Many commercial and military applications would benefit from the availability of room temperature, high-power, semiconductor laser systems that could cover the entire mid-IR band. In particular, high-power, high-brightness 4-pm lasers would be very useful for infrared countermeasures. Antimonide-based semiconductor lasers, both electrically and optically pumped, have exhibited high power [1-4], but for many systems applications they should also have high power conversion efficiency and good beam quality at these longer wavelengths. The short-term requirements for high-power, quasi-CW lasers operating near 4 um are being addressed by the development of cryogenically cooled, Optically Pumped Semiconductor Laser (OPSL) based systems. While the first generation of OPSLs were based on variations of diode laser designs, it is now realized that highperformance OPSLs must be designed with the specific consideration of the detailed physics of optically pumped lasers. In optically pumped 4-jim lasers reported to date, the active region serves both as the gain region and also to absorb the incident pump power. To effectively absorb a large fraction of the incident pump radiation, the laser active region is typically designed to be relatively thick. For previously demonstrated double heterostructure (DH) OPSLs, this means using greater than 1-pam-thick InAsSb active regions. For normal QW OPSLs, often >50 quantum wells are used, since the pump absorption in each Quantum Well (QW) is relatively small. The pump absorption * This work was sponsored by the Air Force Research Laboratory, Department of the Air Force under AF Contract No. F19628-95-C-002. The opinions, interpretations, conclusions and recommendations are those of the authors and are
Data Loading...
