Concept of a Prism Spectrograph for Infrared Linear Array Detectors

Time resolved infrared investigations on the kinetics of objects of interest can be performed by means of Fourier transform infrared spectroscopy. However, this method finds its limits for non-cycling systems or systems with low recovering dynamics having kinetics under investigation faster than the millisecond time regime.
In contrast to standard Fourier transform spectrometers dispersive spectrometers based on prisms or dispersion gratings make the utilization of linear array detectors possible for single-shot operation. They have no moving components mechanically limiting the speed of detection which is now only determined by the signal read-out of the detector itself and can be as fast as in the order of microseconds.
Here, we discuss the concept of an IR spectrometer suitable for linear array detection and broadband infrared synchrotron radiation as a source. The dispersive component of the spectrograph is based on a group of prisms. Obviously, the spectral resolution possible to obtain by a linear pixel detector depends on the number of pixels. Since most of linear-array detectors sensitive in the mid-infrared spectral region consist of either 64 or 128 pixels only, the spectrometer design factors the limited number of pixels over the spectral region of interest for ensuring an optimal spectral resolution.