HIGH-RESOLUTION DIODE-LASER AND HETERODYNE SPECTROSCOPY WITH APPLICATIONS TOWARD REMOTE-SENSING

The recent developments of IR heterodyne and high resolution spectrosc opy at the University of Cologne are presented. By using an impedance matched HEMT amplifier together with newly developed HgCdTe-mixers ver y low noise temperatures of 2100 K (DSB, corrected) have been achieved , which is only 50% above the quantum limit. In addition, very broad b anded detection of the heterodyne signals was obtained with a 1.4 GHz, 2000 channel acousto-optical spectrometer. First results with a tunea ble infrared diode laser as local oscillator have been obtained. For t he interpretation of atmospheric absorption signals laboratory measure ments of pressure effects are made using infrared diode laser spectros copy with very high frequency resolution by frequency stabilization of the laser, and very low noise data acquisition by signal averaging me thods.