Vacuum grating spectrometer for the mid and far infrared.

Area of Science:

• Spectroscopy
• Infrared Spectroscopy
• Instrument Development

Background:

• High-resolution spectroscopy requires stable environments to minimize interference.
• Vacuum chambers are crucial for eliminating atmospheric absorption and improving spectral quality.
• Large aperture spectrometers enhance light throughput and signal-to-noise ratio.

Purpose of the Study:

• To describe the construction and performance of a novel single beam, large aperture spectrometer.
• To evaluate the spectrometer's capabilities in a vacuum environment.
• To demonstrate the instrument's utility with illustrative gas spectra.

Main Methods:

• Construction of a Czerny-Turner monochromator spectrometer (90 cm focal length) within a vacuum chamber.
• Utilized large plane gratings (up to 23 cm x 18 cm) with a Merton nut drive.
• Employed a Golay detector for spectral measurements.

Main Results:

• Achieved spectral resolution of approximately 0.12 cm⁻¹ at 1000 cm⁻¹.
• Obtained resolution of 0.20–0.30 cm⁻¹ in the 300–27 cm⁻¹ range.
• Successfully recorded spectra for ammonia, water vapor, and glyoxal.

Conclusions:

• The vacuum-enclosed spectrometer is a high-performance instrument for infrared analysis.
• The design facilitates high-resolution measurements of gaseous samples.
• Demonstrated applicability for analyzing atmospheric and molecular gases.