Terahertz Devices: Tunable and Mode-Locked p-Ge THz Laser
Abstract
Practical innovations for the far-infrared p-Ge laser were developed to enable commercial applications. New electrodynamic p-Ge laser designs were demonstrated, including an open semiconfocal cavity, dielectric SrTiO3 laser mirrors, and an electrically-controlled intra-cavity wavelength selector, which remarkably improve characteristics and reliability. These cavity designs also allow non-contact optical modulation of the laser gain by external near-infrared radiation, which may potentially replace high-power electrical modulation for generating picosecond far-infrared laser pulses. A new low-cost technique was developed to make uniform ohmic contacts for high-voltage excitation of the active crystal. Novel solid-state excitation electronics were tested as replacement for traditional vacuum-tube pulsers. A NdFeB permanent magnet assembly proved capable of providing the field necessary for laser oscillation. This test led to a next-generation SmCo magnet-assembly concept for replacing the traditional superconducting solenoid. A closed cycle refrigerator was shown to be an adequate replacement of liquid helium for cooling the laser crystal. Hence, a low-cost, all-solid-state, compact, turn-key, far-infrared laser featuring 1-4 THz tunability, waft peak powers, and pico-second pulse capability has been shown to be technically feasible. This laser will have applications in airborne and satellite communications, chemical sensing, and non-destructive testing.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 2001
- Accession Number
- ADA395126
Entities
People
- Chris Fredricksen