Coherent light generators – Particular active media – Semiconductor
Patent
1994-04-04
1995-10-10
Davie, James W.
Coherent light generators
Particular active media
Semiconductor
372 43, H01S 319
Patent
active
054577098
ABSTRACT:
This application discloses, to the best of our knowledge, the first unipolar laser. An exemplary embodiment of the laser was implemented in the GaInAs/AlInAs system and emits radiation of about 4.2 .mu.m wavelength. Embodiments in other material systems are possible, and the lasers can be readily designed to emit at a predetermined wavelength in a wide spectral region. We have designated the laser the "quantum cascade" (QC) laser. The QC laser comprises a multilayer semiconductor structure that comprises a multiplicity of essentially identical undoper "active" regions, a given active region being separated from an adjoining one by a doped "energy relaxation" region. In a currently preferred embodiment each active region comprises three coupled quantum wells designed to facilitate attainment of population inversion. In the currently preferred embodiment the energy relaxation regions are digitally graded gap regions. However, other energy relaxation regions are possible. The unipolar plasma in a unipolar laser can be manipulated by means of an electric "control" field, facilitating, for instance, beam steering or external control of the modal gain of the laser. Means for accomplishing this are discussed.
REFERENCES:
patent: 5311009 (1994-05-01), Capasso et al.
"Possibility of the Amplification of Electromagnetic Waves in a Semiconductor with a Superlattice", by R. F. Kazarinov et al., Soviet Physics-Semiconductors, vol. 5, No. 4, Oct., 1971, pp. 707-709.
"Evaluation of the Feasibility of a Far-infrared Laser Based on Intersubband Trransitions in GaAs Quantum Wells", by S. I. Borenstain, Applied Physics Letters, vol. 55 (7), 14 Aug. 1989, pp. 654-656.
"Feasibility of Far-infrared Lasers Using multiple Semiconductor Quantum Wells," by Q. Hu, Applied Physics Letters, vol. 59(23), 2 Dec. 1991, pp. 2923-2925.
"Possibility of Infrared Laser in a Resonant Tunneling Structure," by A. Kastalsky et al., Applied Physics Letters, vol. 59 (21), 18 Nov. 1991, pp. 2636-2638.
"Carrier Transport and Intersubband Population Inversion in Coupled Quantum Wells", W. M. Yee et al., Applied Physics Letters, vol. 63 (8), 23 Aug. 1993, pp. 1089-1091.
"Periodic Negative Conductance by Sequential Resonant Tunneling Through an Expanding High-field Superlattice Domain", by K. K. Choi et al., Physical Review B, vol. 35, No. 8, 15 Mar. 1987-I, pp. 4172-4175.
"Band Nonparabolicity Effects in Semiconductor Quantum Wells," by D. F. Nelson et al., Physical Review B, vol. 35, No. 14, 15 May 1987, pp. 7770-7773.
"Quantum-well Intersub-band Electroluminescent Diode at .lambda.=5.mu.m," by J. Faist et al., Electronics Letters, vol. 29, No. 25, 9 Dec. 1993, pp. 2230-2231.
"Phonon Limited Intersubband Lifetimes and Linewidths in a Two-dimensional Electron Gas," by J. Faist, Applied Physics Letters, vol. 64 (7), 14 Feb. 1984, pp. 872-874.
"Pseudo-quaternary GaInAsP Semiconductors: A new Ga.sub.0.47 In.sub.0.53 As/InP Graded Gap Superlattice and its Applications to Avalanche Photodiodes", by F. Capasso, Applied Physics Letters, vol. 45 (11), 1 Dec. 1984, pp. 1193-1195.
"Staircase Solid-State Photomultipliers and Avalanche Photodiodes with Enhanced Ionization Rates Ratio," by F. Capasso, IEEE Transactions on Electron Devices, vol. ED-30, No. 4, Apr. 1983, pp. 381-390.
"Mid-infrared Field-tunable Intersubband Electroluminescence at Room Temperature by Photon-assisted Tunneling in Coupled-quantum Wells," by J. Faist, Applied Physics Letters, vol. 64(9), 28 Feb. 1994, pp. 1144-1146.
Capasso Federico
Cho Alfred Y.
Faist Jerome
Hutchinson Albert L.
Luryi Serge
AT&T IPM Corp.
Davie James W.
Pacher Eugen E.
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