排序方式: 共有41条查询结果,搜索用时 15 毫秒
11.
Kohler R. Gmachl C. Capasso F. Tredicucci A. Sivco D.L. Cho A.Y. 《Photonics Technology Letters, IEEE》2000,12(5):474-476
Widely tunable, single-mode quantum cascade distributed feedback (QC-DFB) lasers based on a complex coupling scheme and operating in the wavelength range of the CO2 laser (λ≈9.5-10.5 μm) are reported. Dynamic single-mode emission up to high current levels is obtained. The continuous single-mode tuning range is 150 nm, while the tuning range of the equivalent Fabry-Perot laser is ~400 nm. By homogeneously reducing all layer thicknesses by 10%, the wavelength coverage of a single QC-laser design can be extended to cover one entire regular band of the fundamental CO2 laser spectrum 相似文献
12.
Danworaphong S Calasso IG Beveridge A Diebold GJ Gmachl C Capasso F Sivco DL Cho AY 《Applied optics》2003,42(27):5561-5565
The quantum-cascade laser can be used as an infrared source for a small portable photoacoustic trace gas detector. The device that we describe uses a quantum-cascade laser without collimating optics mounted inside an acoustic resonator. The laser is positioned in the center of a longitudinal resonator at a pressure antinode and emits radiation along the length of the resonator exciting an axially symmetric longitudinal acoustic mode of an open-ended cylindrical resonator. Experiments are reported with an 8-microm, quasi-cw-modulated, room-temperature laser used to detect N2O. 相似文献
13.
Colombelli R. Gmachl C. Sergent A.M. Sivco D.L. Narimanov E.E. Podolskiy V.A. Cho A.Y. Capasso F. 《IEEE journal of selected topics in quantum electronics》2006,12(1):66-70
We report the demonstration of surface-plasmon microcylinder quantum cascade lasers with circular and deformed resonators. An improved self-alignment fabrication technique was developed that allows the use of wet etching, necessary to achieve smooth and clean surfaces, in combination with the deposition of the surface-plasmon-carrying metal layer up to the very edge of the resonator, where the optical mode is mostly located. The diameter of the microcylinders ranges from 75 to 180 /spl mu/m while their deformation coefficient /spl epsiv/ ranges from /spl epsiv/=0 to /spl epsiv/=0.32. Circular microcylinder lasers show a reduction of /spl sim/50% of the threshold current density with respect to devices with standard ridge-waveguide resonators. On the other hand, highly deformed microcylinder lasers exhibit a complex mode structure, suggesting the onset of chaotic behavior. 相似文献
14.
Straub A. Gmachl C. Sivco D.L. Sergent A.M. Capasso F. Cho A.Y. 《Electronics letters》2002,38(12):565-567
Quantum cascade distributed feedback (QC-DFB) lasers based on a heterogeneous-cascade two-wavelength active waveguide core and a multisectioned cavity featuring two different Bragg gratings are demonstrated. Optimised lasers display singlemode emission at λ~5.0 and 7.5 μm simultaneously and a tunability on both modes equal to single-wavelength QC-DFB lasers 相似文献
15.
C. Gmachl J. Faist J.N. Bailargeon F. Capasso C. Sirtori D.L. Sivco S.N.G. Chu A.Y. Cho 《Photonics Technology Letters, IEEE》1997,9(8):1090-1092
Quantum-cascade distributed-feedback lasers (QCDFB) with a grating close to the active region are reported. Feedback is provided by the grating in a refractive index-dominated coupling scheme. Reliable single-mode emission at /spl lambda//sub cm//spl ap/5.4 /spl mu/m with a side-mode suppression ratio (SMSR) /spl ap/30 dB is observed. The laser is continuously tunable over 40 nm with a coefficient of /spl Delta//spl lambda///spl Delta/T/spl ap/0.37 nm/K in the temperature range from 200 K to 300 K. Comparison with Fabry-Perot QC lasers shows an overall improved performance of QC-DFB lasers. 相似文献
16.
Malis O. Belyanin A. Sivco D.L. Chen J. Sergent A.M. Gmachl C. Cho A.Y. 《Electronics letters》2004,40(25):1586-1587
Milliwatt second harmonic power at 4.45 /spl mu/m was achieved in InP lattice-matched quantum cascade lasers with monolithically-integrated resonant nonlinear cascades and modal phase matching. The use of an InP top-cladding layer and high-reflectance coating on the laser back facet enabled high linear laser power and consequently record nonlinear power. 相似文献
17.
A computational and experimental analysis of rollover in high-performance lambda ~ 8 mum quantum-cascade (QC) lasers is presented. In addition to conventional, thermal rollover, which is also a common cause of power rollover in diode lasers, ";Stark-effect"; rollover is observed. While both effects can occur in the same QC laser design, thermal and Stark-effect rollover are shown to be the dominating factor for high-temperature continuous wave operated, and pulsed low-temperature operated and low-doped lasers, respectively. Additionally, the role of the continuum above the wells and barriers is discussed for both effects. 相似文献
18.
Gmachl C. Hwang H.Y. Paiella R. Sivco D.L. Baillargeon J.N. Capasso F. Cho A.Y. 《Photonics Technology Letters, IEEE》2001,13(3):182-184
Quantum cascade lasers have been fabricated with chalcogenide lateral waveguide claddings. Several-micrometer thick Ge0.25Se0.75 glass has been deposited by pulsed laser ablation onto the sidewalls of narrow, deep etched laser ridges. Due to the intrinsically low mid-infrared attenuation of the chalcogenide material, the waveguide loss of the lasers is significantly reduced, by up to ~50%, depending on the ridge width, when compared to conventional ridge waveguides. This resulted in an improved overall laser performance, such as a reduction of the threshold current density, an increase in slope efficiency, and an improved temperature performance 相似文献
19.
Colombelli R. Tredicucci A. Gmachl C. Capasso F. Sivco D.L. Sergent A.M. Hutchinson A.L. Cho A.Y. 《Electronics letters》2001,37(16):1023-1024
Continuous wave laser action has been achieved in a superlattice quantum cascade device operating on surface plasmon waveguide modes. The emission wavelength λ~19 μm is by far the longest ever reported for continuous wave III-V semiconductor lasers. The output power at cryogenic temperature is of the order of the mW 相似文献
20.
Afusat O. Dirisu Grace Silva Zhijun Liu Claire F. Gmachl Fred J. Towner John Bruno Deborah L. Sivco 《Photonics Technology Letters, IEEE》2007,19(4):221-223
We demonstrate the reduction of the facet reflectivity of quantum-cascade lasers (QCLs) by using subwavelength gratings. The gratings were fabricated on lambda=4.9- and 9.8-mum QCLs using focused ion beam milling. Reflectivities as low as 1%-3% for the 4.9-mum QCL and as low as 4%-8% for the 9.8-mum QCL are reported 相似文献