Abstract: An interferometry apparatus comprises one or more beam generators, a detector, and a plurality of optical paths along which one or more beams of light propagate. Disposed along at least one of the optical paths is an apodization mask to shape one of the beams.

Abstract: An optical component especially suited for common path heterodyne interferometry comprises a symmetric dual-periscope configuration. Each periscope is substantially identical to the other with regard to certain design aspects. The resulting design is an optical component that is highly stable with variations in temperature and angular deviations.

Abstract: Embodiments of the present invention are directed to reducing cyclic error in the beam launcher of an interferometer. In one embodiment, an interferometry apparatus comprises a reference beam directed along a reference path, and a measurement beam spatially separated from the reference beam and being directed along a measurement path contacting a measurement object. The reference beam and the measurement beam have a single frequency. At least a portion of the reference beam and at least a portion of the measurement beam overlapping along a common path. One or more masks are disposed in the common path or in the reference path and the measurement path to spatially isolate the reference beam and the measurement beam from one another.

Abstract: Embodiments of the present invention are directed to a simple apparatus and a convenient and accurate method of mounting the components to form an off-axis reflective optical apparatus such as a collimator. In one embodiment, an off-axis reflective optical apparatus comprises a mounting block having a ferrule holder support surface and an off-axis reflector support surface which is generally perpendicular to the ferrule holder support surface. An optical reflector is mounted on the off-axis reflector support surface and has a reflected beam centerline. The optical reflector has a conic reflective surface and a conic center. A ferrule holder is mounted on the ferrule holder support surface. The ferrule holder provides a ferrule for coupling to an optical fiber and orienting a fiber tip of the optical fiber along a fiber axis toward the optical reflector. The fiber axis is nonparallel to the reflected beam centerline.

Abstract: A system and method for determining wind velocity. The LIDAR 104 transmits a plurality of laser pulses. The paths of the laser pulses surround a center line (206) that does not coincide with a vertical axis (706) intersecting the LIDAR (104), i.e., an off-vertical scan. Each laser pulse reflects off particles in the air at a given location. This location is the intersection of the path of each LIDAR pulse and the target altitude. The target altitude is the altitude at which the wind velocity is to be determined. The reflected pulses are received by the LIDAR (104). The invention groups the received LIDAR pulses according to the altitude at which they were reflected, as opposed to the distance each pulse travels. Grouping the received pulses in this manner enables the invention to perform an off-vertical scan that accurately determines the wind velocity at a target altitude. The received laser pulses have an associated Doppler shift.

Abstract: An optical coordinate transfer assembly provides angular correlation between spatially separated objects. In a particular embodiment of the invention, roll, pitch and yaw of a second directional device 12 relative to a first directional device 11 can be measured (and correction and/or compensation therefor can be made) using an optical alignment sensor 20 mounted on the first directional device 11 and a rooftop-mirror/lens assembly 21 mounted on the second directional device 12. Light beams projected from the optical alignment sensor 20 are reflected by reflector devices 35 and 36 on the rooftop-mirror/lens assembly 21 to linear arrays 69, 70 and 78 of photodetectors, which generate electronic signals indicating angular discrepancies between the orientations of the first and second directional devices 11 and 12 in three degrees of freedom to sub-microradian accuracy over a wide range of measurements.