An Infrared Beam Projector for Use in Fourier Transform Spectroscopy

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.