High-sensitivity mid-infrared heterodyne spectrometer with a tunable diode laser as a local oscillator.

A new mid-IR heterodyne spectrometer, which is intended to be applied for atmospheric and astrophysical studies, is presented. The spectrometer uses a frequency-stabilized tunable diode laser as a local oscillator. Owing to the low output power of available single-mode diode lasers, a newly developed confocal-ring resonator, the diplexer, is used to superimpose the source signal efficiently with that of the local oscillator. Additionally, the diplexer serves as an optical filter that establishes controlled optical feedback between the laser diode and the detector, which allows stable laser operation with linewidths of the order of 1 MHz. The heterodyne signal from the HgCdTe detector is analyzed by means of a 1.4-GHz acousto-optical spectrometer. With this setup we find system temperatures as low as 4400 K (double sideband), that is, approximately a factor of 6 of the quantum limit.

[1]  B. Parvitte,et al.  Atmospheric laser heterodyne detection , 1996 .

[2]  R. Schieder.  High resolution diode laser and heterodyne spectroscopy with applications toward remote sensing , 1994 .

[3]  G. Winnewisser,et al.  Measurements of Foreign Gas Pressure Shift and Broadening Effects in the (1-0) Band of CO with N2 and Ar , 1993 .

[4]  M. Tacke,et al.  Stabilization of 3.3 and 5.1 μm lead-salt diode lasers by optical feedback , 1992 .

[5]  Volker Tolls,et al.  New Cologne acousto-optical spectrometer projects , 1990 .

[6]  M. Taguchi,et al.  Laser heterodyne spectrometer using a liquid nitrogen cooled tunable diode laser for remote measurements of atmospheric O(3) and N(2)O. , 1990, Applied optics.

[7]  C. T. McElroy,et al.  Heterodyne spectrophotometry of ozone in the 9.6-μm band using a tunable diode laser , 1990 .

[8]  Volker Tolls,et al.  The Cologne acousto optical spectrometers , 1989 .

[9]  Charles Howard Henry,et al.  Instability of semiconductor lasers due to optical feedback from distant reflectors , 1986 .

[10]  Govind P. Agrawal,et al.  Line narrowing in a single-mode injection laser due to external optical feedback , 1984 .

[11]  M. Mumma,et al.  Remote sensing by IR heterodyne spectroscopy. , 1983, Applied optics.

[12]  D. Buhl,et al.  Tunable diode-laser heterodyne spectrometer for remote observations near 8 microm. , 1982, Applied optics.

[13]  J. Hoell,et al.  Optical feedback effects on the performance of Pb(1-x)Sn(x)Se semiconductor lasers. , 1979, Applied optics.

[14]  David Buhl,et al.  NH3 spectral line measurements on Earth and Jupiter using a 10 μm superheterodyne receiver , 1977 .

[15]  D. Buhl,et al.  Sensitivity limits of an infrared heterodyne spectrometer for astrophysical applications: errata. , 1976, Applied optics.

[16]  T. Blaney.  Signal-to-noise ratio and other characteristics of heterodyne radiation receivers , 1975 .

[17]  M. J. Feldman,et al.  MMA Memo 161 Receiver Noise Temperature, the Quantum Noise Limit, and the Role of the Zero-Point Fluctuations * , 1996 .