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Extending high-finesse cavity techniques to the far-infrared
Bridget Alligood DePrince1, Blithe E Rocher, Anne M Carroll
1Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA.
The Review of Scientific Instruments
|August 2, 2013
Summary
Researchers developed a novel high-finesse cavity using wire-grid polarizers for far-infrared spectroscopy. While achieving quality factors of 10(5), current technology limits sensitivity for cavity ringdown spectroscopy.
Area of Science:
- Physics
- Spectroscopy
- Optics
Background:
- High-finesse Fabry-Perot resonators are crucial for sensitive spectroscopy in microwave and near-infrared regions.
- Hardware limitations, particularly optics reflectivity and detector speed, have restricted their use in far-infrared wavelengths.
Purpose of the Study:
- To develop a novel high-finesse cavity suitable for far-infrared spectroscopy.
- To investigate the feasibility of extending cavity ringdown spectroscopy to far-infrared wavelengths.
Main Methods:
- Designed and implemented a novel high-finesse cavity utilizing wire-grid polarizers as reflective surfaces.
- Achieved quality factors (Q) on the order of 10(5) at 250 GHz.
- Evaluated the performance limitations for cavity ringdown spectroscopy at far-infrared wavelengths.
Main Results:
- Demonstrated a high-finesse cavity with Q factors of approximately 10(5) at 250 GHz.
- Predicted a minimum detectable absorption coefficient (αmin) of ~10(-7) cm(-1) with a 120 cm cavity and ~500 ns detector response time.
- Identified current optics and detectors as limiting factors for spectrometer performance.
Conclusions:
- The novel cavity design shows promise for far-infrared applications.
- Advancements in detector technology (faster and more sensitive) are necessary for practical implementation and significant improvements in cavity ringdown spectroscopy at far-infrared wavelengths.
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