Aperture extender for autocollimators and telescopes having index-matching gel or fluid between prism facets
The disclosure introduces a technique to expand the aperture of an optical system like an Autocollimator by interconnecting two or more rhomboidal prisms in a sequential manner. This method involves securing the initial rhomboid to the autocollimator's aperture using a rotating component at its base. Subsequently, a second rotating component is attached to the exit end of the first rhomboid, enabling individual rotation for both rhomboids. These prisms are coated with distinct partial mirror coatings. The processing of the reflected image from these rhomboids are conducted to ascertain the deviation in the line of sight caused by their presence and positioning. A microprocessor computes the measurement of the back reflected beams concerning the rhomboids' positions, determining beam deviations resulting from imperfections in the manufacturing of the rhomboids. The identified imperfections are employed to rectify the outcomes derived from the assembly of rhomboids, ensuring heightened precision in the collected data.
1 . An aperture extender system for optical devices, comprising a first rhomboidal prism and a second rhomboidal prism interconnected in series; a first rotating coupling securing the first rhomboidal prism to an autocollimator's aperture such that the first rhomboidal prism rotates concentrically about the autocollimator's optical axis;
a second rotating coupling securing the second rhomboidal prism to an exit facet of the first rhomboidal prism such that the second rhomboidal prism rotates about the optical axis of an exiting beam; wherein a sealed cavity is formed between adjacent facets of the rhomboidal prisms and contains an index-matching gel or fluid that eliminates inter-reflections during rotation;
wherein each rhomboidal prism includes a partial-mirror coating configured to generate wavelength-selective back-reflected diagnostic images; and
wherein a microprocessor receives the back-reflected diagnostic images and computes correction data for line-of-sight deviations introduced by prism manufacturing or alignment imperfections, such that the interconnected rotating rhomboidal prisms widen the effective aperture of the autocollimator beyond its original physical limits.
2 . The system of claim 1 , wherein the first rotating coupling and the second rotating coupling comprise magnetically-biased annular bearings forming a sealed mechanical interface that maintains the index-matching gel or fluid within the cavity while allowing independent rotation of each rhomboidal prism.
3 . An application of the aperture extender system of claim 1 , wherein the first rhomboidal prism and the second rhomboidal prism are inter-rotated to position an output aperture of the system over a selectable region substantially larger than the original aperture of the autocollimator.
4 . The system of claim 1 , further comprising a penta-prism attachment positioned at the autocollimator's output and configured to redirect the autocollimator's original optical axis prior to entering the first rhomboidal prism, wherein the redirection provided by the penta-prism is combined with rotation of the first and second rhomboidal prisms to expand both angular reach and spatial coverage of the aperture extender system.
5 . A method for assessing and correcting inaccuracies in rhomboidal prisms integrated into an aperture extender system, the method comprising: projecting a calibration beam from an autocollimator through a first rhomboidal prism and a second rhomboidal prism;
receiving partial back-reflections generated by partial-mirror coatings on facets of each rhomboidal prism; detecting the back-reflections with an imaging sensor of the autocollimator; identifying, via wavelength separation or coating characteristics, which back-reflections correspond to which rhomboidal prism;
computing, by a microprocessor, angular and positional deviations attributable to manufacturing or alignment imperfections in each rhomboidal prism; and
applying correction data to measurements acquired through the aperture extender system to compensate for the computed deviations, wherein an index-matching gel or fluid disposed between adjacent prism facets reduces inter-reflections that would otherwise corrupt the diagnostic reflections.
6 . A method of operating an aperture extender system for optical devices, the method comprising:
interconnecting a first rhomboidal prism and a second rhomboidal prism in series;
securing the first rhomboidal prism to an autocollimator's aperture using a first rotating coupling that allows rotation about the autocollimator's optical axis;
employing a microprocessor to compute the measurement of back-reflected beams concerning the rhomboids' positions, detecting imperfections in the rhomboids' manufacturing;
utilizing distinct partial mirror coatings on the rhomboids and processing reflected images to assess the deviation in the line of sight caused by their positioning; and
attaching a second rotating rotating coupling to an exit facet of the first rhomboidal prism to support rotation of the second rhomboidal prism about an axis of an exiting beam;
filling a sealed cavity between adjacent prism facets with an index-matching gel or fluid to eliminate inter-reflections during rotation;
generating partial back-reflections from partial-mirror coatings on facets of the rhomboidal prisms;
processing the reflected images to determine line-of-sight deviations introduced by prism positioning or imperfections; and
computing by a microprocessor, correction values based on the back-reflections to compensate for prism-induced deviations during measurement.