Flight qualification of a diode laser for path difference determination of a high-resolution Fourier transform spectrometer

Abstract

Diode lasers offer a lightweight, rugged, and economic alternative to other types of laser source, but they often do not provide long-term stability and spectral purity of emission. We have developed a stabilized, near-infrared diode laser source that is capable of as much as 20 mW of single-mode output power for the effective replacement of a He-Ne laser in the path difference measuring system of a high-resolution (1.25-m maximum path difference) Fourier transform spectrometer. Laser characterization has been performed both in laboratory measurements and in flight tests, resulting in a relative frequency stability of better than 10(-6) on a 6-h flight.

Technical Note: REFIR-PAD level 1 data analysis and performance characterization

“…The interferometer scanning mirror position is monitored by means of a reference laser interferometer using a temperature stabilized solid state semiconductor laser source at the wavelength of 780 nm (Bianchini et al, 2000). The maximum resolution achievable by the system is 0.25 cm −1 , a typical scan at the operative resolution of 0.5 cm −1 is performed in about 30 s.…”

Emission Fourier transform spectroscopy for remote sensingof the Earth's atmosphere

“…The FIR interferometer (fi g. 7) is based on a double parallelogram scheme that through a folding of the optical path and the simultaneous movement of both mirrors provide a maximum Optical Path Difference (OPD) between the two arms of the interferometer equal to 1.25 m, containing the optics in a cube with a side of about 0.5 m. Accurate measurement of OPD is obtained through a reference laser interferometer based on a frequency-stabilised diode laser source and following the same optical path of the far infrared radiation (Bianchini et al, 2000).…”

Technical Note: REFIR-PAD level 1 data analysis and performance characterization

“…Frequency calibration is performed using the reference laser (Bianchini et al, 2000). The reference source stability allows to use only a single measurement, performed using atmospheric line centers, in order to calculate laser frequency.…”

“…The interferometer scanning mirror position is monitored by means of a reference laser interferometer using a temperature stabilized solid state semiconductor laser source at the wavelength of 780 nm (Bianchini et al, 2000). The maximum spectral resolution achievable by the system is 0.25 cm −1 , corresponding to a maximum optical path difference of 2 cm (double-sided interferogram).…”