Model 303 Prism Monochromator a tunable sharp cut filter in UV Raman applications Vis-NIR wide range spectrograph with no multiple orders MWIR or LWIR spectrograph with no multiple orders and low dispersion for wide wavelength coverage prism materials selected for wavelength rnage and dispersion requirement

The Model 303 Prism Spectrometer is a 250-mm focal length Czerny-Turner. It uses a prism in Littrow configuration for refraction. This geometry delivers an f/3.5 aperture ratio system with excellent throughput.

Prism instruments do not have multiple diffracted orders like gratings and are capable of providing extremely low dispersions. This unit may be used with slits and a scanning motor as a conventional scanning monochromator (as predisperser, etc.) or with a wide exit focal plane array like CCD in the Visible or bolometer array in the Infrared. If your requirement calls mainly for a predisperser used to narrow bandpass or order sort for a grating monochromator you can also consider our Model 608 prism pre- disperser.

Throughput and Dispersion of this system vary with the index of refraction of the material selected for the prism. Typical prism materials include SiO, ZnSe, NaCl and occasionally KRS-5. Use of different prism materials enables operation in a very wide wavelength range. Prism material and wedge angle are generally selected to meet the Dispersion requirement in the wavelength region of interest.

Since the refractive index of materials very with wavelength the Prism Spectrometer does not have a linear wavelength readout. We provide these instruments with a calibrated look up table based on actual and instrument specific data, not theoretical calculations. The look up table can be applied to software used for scanning or for wavelength axis calibration of focal plane arrays.

PDF format Data Sheet for the prism monochromators, Models 608 and 303 available here

Variation of Dispersion due to Refractive Index across the working range of the Prism Predisperser