Ultrahigh-resolution broadband spectrometer based on grating-beamsplitter interferometer

Abstract

An ultrahigh-resolution broadband spectrometer based on a grating-beamsplitter interferometer is presented, in which a transmission grating serves not only as a beamsplitter for the interferometer but also as a dispersive element to divide a wide spectral band into multiple narrow spectral bands. The distinctive design reduces the number of optical components of the instrument and simplifies the structure of the instrument. For one scan period, this spectrometer generates multiple interferograms simultaneously, each interferogram covering a separate wavelength range is received by a separate pixel of the linear detector, and the sum of the spectra recovered from all interferograms constitutes a continuous broadband spectrum. The relevant formulas and preliminary design calculation are provided. The simulation is shown by two examples within the spectral range from 300 nm to 500 nm and 900 nm to 1600 nm. This spectrometer will be suitable for ultrahigh-resolution broadband spectral measurements.