摘要 |
In an interferometric apparatus the path of the output beam of a rotary Optical Path Difference scanning assembly leading to an electrically responsive detector is maintained substantially fixed in space for any scan angle within predetermined limits, thus obviating a serious drawback of a prior art proposal wherein the output beam translates significantly over the detector face with changes in scan angle, with the result that the detector output is vitiated by totally spurious variations of the energy reaching it. In one embodiment, the scanning assembly comprises a beam splitter having a semi-reflective layer the output face of which cooperates with the face of an output mirror normal thereto, the axis of rotation being substantially coincident with the line of intersection between the prolongation planes of the two faces. A Fourier Transform spectrophotometer embodying the assembly is also described.
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