A simple spectrogram model for high-accuracy spectral calibration of VIPA spectrometers

Area of Science:

• Optics and Spectroscopy
• Instrumental Science

Background:

• Virtually Imaged Phased Array (VIPA) spectrometers offer compact design, high spectral resolution, and broad wavelength coverage.
• Accurate wavelength calibration for VIPA spectrometers is challenging due to etalon non-linearity and spectrometer design.

Purpose of the Study:

• To develop a simple and accurate wavelength calibration method for VIPA spectrometers.
• To address the challenge of non-linear dispersion in VIPA etalons.

Main Methods:

• Developed a novel five-parameter spectrogram model by simplifying the VIPA etalon phase-matching equation.
• Accounted for the angle between the camera and the dispersion direction.

Main Results:

• The model achieved frequency accuracy better than one pixel.
• Successfully demonstrated performance by measuring the CO2 absorption spectrum (1.42–1.45 μm) with a custom near-infrared VIPA spectrometer.

Conclusions:

• The new method provides a simple, accurate, and easily solvable approach for VIPA spectrometer wavelength calibration.
• This technique facilitates broader applications of VIPA spectrometers in precision measurements.