When the infrared spectrum of a sample is to be recorded, it is not always convenient to locate the sample and its supportive apparatus within the sample chamber of a spectrometer. The beam-projecting device described herein permits redirection of the infrared beam from the sample chamber to a location outside the spectrometer. Thus the effort required to obtain infrared spectra of in situ samples using a Fourier transform spectrometer is greatly reduced. The unique capability of this infrared beam projector is its ability to accommodate the large diameter beam of a Fourier transform spectrometer, even in the far infrared mode, without appreciable loss of throughput.
G. T. Reedy and A. C. Gilby, "An Infrared Beam Projector for Use in Fourier Transform Spectroscopy," Appl. Spectrosc. 29, 532-532 (1975)