Spectral resolution enhanced static Fourier transform spectrometer based on a birefringent retarder array

The principle and experimental demonstration of a spectral resolution enhanced static Fourier transform spectrometer (SESFTS) is presented. The device, which is based on a birefringent retarder array and a Wollaston prism, offers significant advantages over previous static Fourier transform (FT) implementations. Specifically, its use of an ultra-compact common-path interference structure creates a simple and robust spectral resolution enhanced spectrometer while preserving their high throughput and wide free spectral range. The operation principle of the device is explained in detail with a design example with a spectral resolution of 7 cm^-1, which is nearly two orders of magnitude higher than that of a conventional static FT spectrometer with a similar CCD detector. An experimental demonstration is performed by the measurement of a gas charge lamp and three diode laser sources with a SESFTS prototype working in 400-1000 nm with an approximate 25 cm^-1 spectral resolution.