Tunable heterodyne spectrometer in the 9 mu m range with selected lead-salt diodes

Heterodyne spectrometry is a potentially powerful technique for astronomica l or geophysical investigations. A heterodyne receiver works by mixing the radiation under study with the laser radiation from a local oscillator (LO) on a fast photodetector. The described apparatus uses Pb-salt diodes as th e LO and operates between 1050 and 1150 cm(-1). The effects of the characte ristics of the diode on the performances of the heterodyne receiver are det ailed. Ground-based heterodyne atmospheric spectra of the nu(1) band of ozo ne using the sun as a source are presented. (C) 1999 Elsevier Science B.V. All rights reserved.