URSIES: an Ultravariable Resolution Single Interferometer Echelle Scanner

Area of Science:

• Spectroscopy
• Optical Instrumentation

Background:

• Traditional grating scanners face limitations in resolution and light throughput.
• Accurate spectral analysis requires minimizing stray light and maximizing signal detection.

Purpose of the Study:

• To introduce and evaluate a new spectroscopic instrument, URSIES, designed for enhanced performance.
• To demonstrate the advantages of URSIES in terms of resolution, light gain, and stray light reduction.

Main Methods:

• Utilized a Fabry-Perot interferometer in a Ramsay mount coupled with an echelle Hilger monochromator.
• Employed pinholes instead of slits and enclosed the instrument in a Freon-filled pressure chamber.
• Implemented photoelectric pulse counting and pressure scanning for spectral recording.

Main Results:

• Achieved a variable spectral resolution from 5.0 Å to 0.005 Å over a broad wavelength range (3500 Å to 13,000 Å).
• Demonstrated a tenfold light gain compared to conventional grating scanners at resolutions of 0.1 Å or better.
• Reported very low out-of-band light (<5% at 0.03 Å resolution) and minimal scattered light (<1% across 4000 Å to 11,000 Å).

Conclusions:

• The URSIES instrument offers significant advantages for high-resolution spectroscopy.
• Its design enables precise spectral measurements with improved sensitivity and reduced artifacts.
• URSIES is well-suited for applications requiring detailed analysis of light spectra, including astronomical observations.