Abstract: An optical slipring includes a derotating, transmissive intermediate optical component with an array of lensed optical transmitters and receivers respectively mounted on the rotor and stator. The lensed transmitters receive light from optical fibers, or other light source, and expand the light into a collimated light beam for transmission across the rotor/stator gaps. The lensed receivers receive the expanded, collimated light beams and focus them onto a receiving fiber or photodetector. To make the slipring bi-directional, each lens functions as both a converging and diverging lens and thus as a receiver and transmitter. Collimated light beams minimize light loss caused by the inability to efficiently couple diverging light beams.

Abstract: An optical refractometer for automatically determining the principal indices of a specimen receives an incident radiation beam which is reflected by a first rotatable mirror onto a reflecting surface of a first elliptical mirror wherein the axis of rotation of the first rotatable surface extends through a first focus of the first elliptical mirror. A hemicylinder has a center of curvature at a second focus of the first elliptical mirror and rotatably and translatably mounts a specimen about a first axis and along second and third axes, respectively, such that a portion of the specimen is located at the second focus to receive the reflected incident beam from the first rotatable surface. A second elliptical mirror has third and fourth foci and a second surface for reflecting the incident radiation beam from the second elliptical mirror with an axis of rotation extending through the fourth focus with the third focus being at the first axis coincident with the second focus for producing a reflected beam output.