Accession Number : ADA299452

Title :   Far-Infrared (THz) Lasers Using Multiple Quantum Wells.

Descriptive Note : Final rept. 1 Jun 92-31 May 95,

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE RESEARCH LAB OF ELECTRONICS

Personal Author(s) : Hu, Qing

PDF Url : ADA299452

Report Date : 09 AUG 1995

Pagination or Media Count : 22

Abstract : This project is to develop THz solid state lasers using multiple quantum well (MQW) structures. Based on work in our group and other groups outside MIT in the last few years, we have focused out effort on using double quantum well (DQW) Structures to achieve this goal. In essence, a DQW device is a voltage tunable two level system, as far as the interwell intersubband transition is concerned. Thus, compared to intrawell intersubband transition devices that have been proposed and studied, the DQW device has a greater tolerance for design and fabrication errors. This is a major advantage over Bloch oscillators using superlattices, in which the unavoidable formation of high field domains will lead to a significant misalignment of energy levels through the superlattice. Since the relative energy difference between the lowest two levels in a DQW structure is voltage tunable, the same structure can also be used for far-infrared detection as well as generation, if the initial state lies below the final state. In the current three-year project, we have explored the potential ot far infrared generation and detection using DQWs. We have performed an extensive theoretical study on the radiation properties of DQW structures, such as gain, loss, and efficiency. We have also performed an extensive study using magnetotunneling spectroscopy to accurately determine the relative subband levels in the DQW structures.

Descriptors :   *QUANTUM WELLS, *INFRARED LASERS, OSCILLATORS, SOLID STATE LASERS, SPECTROSCOPY, QUANTUM THEORY, CRYSTAL LATTICES, SUPERLATTICES, FABRICATION, FAR INFRARED RADIATION, ELECTRON TRANSITIONS, ENERGY LEVELS, MISALIGNMENT.

Subject Categories : Lasers and Masers

Distribution Statement : APPROVED FOR PUBLIC RELEASE