Far-infrared heterodyne spectrometer for airborne astronomy

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1988

OSTI ID:6295469

Grossman, E N

Design and construction of a novel heterodyne spectrometer for airborne astronomy in the 50- to 200-..mu..m wavelength range is described, along with laboratory measurements of its performance. A bulk, extrinsic Ge:Ga photoconductor is used as the mixer. Its low bandwidth, determined by the hole-recombination rate, necessitates the use of a continuously tunable local oscillator. This is provided by a far-infrared laser sideband generator, based on a GaAs Schottky diode mounted at the feed of a corner-cube antenna, the latter combination acting as a reflective FIR modulator. The author describes the astronomical and technical context of the project, the constraints the astronomical goals set on the instrument, and the advantages and drawbacks of each of the various broad instrumental strategies available for spectrometer design. He reports on an extensive series of measurements of bandwidth, photoconductive gain, and direct detection responsivity for a series of highly compensated, NTD detectors grown specifically for this purpose. He also describes the operating principles and construction of the FIR laser.

• Research Organization: California Inst. of Tech., Pasadena (USA)
• OSTI ID: 6295469
• Country of Publication: United States
• Language: English

Related Subjects

440300* -- Miscellaneous Instruments-- (-1989)
47 OTHER INSTRUMENTATION
640100 -- Astrophysics & Cosmology
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
DESIGN
ELECTROMAGNETIC RADIATION
FAR INFRARED RADIATION
INFRARED RADIATION
INFRARED SPECTROMETERS
LASERS
MEASURING INSTRUMENTS
PERFORMANCE
RADIATIONS
SCHOTTKY BARRIER DIODES
SEMICONDUCTOR DEVICES
SEMICONDUCTOR DIODES
SPECTROMETERS