Abstract:
The invention concerns an optical grating drive apparatus wherein a carriage for multiple diffraction gratings is movable between a plurality of locations, there being stops to limit carriage movement at such locations in which different gratings are selectively presented in the path of an incident beam; also a plurality of cam followers are shiftable relative to rotary cam means between positions in which different followers selectively engage the cam means and are displaced in response to cam means rotation; the followers and carriage have operative interconnection such that when a selected follower is engaged with the cam means the carriage may occupy alternate locations in order to selectively present corresponding gratings to the beam path; and displacement of a selected follower in response to cam rotation effects rotation of a selected grating in the beam path.
Abstract:
Apparatus for passing light repeatedly through a sample in a sample space comprises two longitudinally separated reflectors one of which is concave and the other of which is planar, the reflectors located to repeatedly reflect a light beam therebetween for passage repeatedly through the sample space.