Abstract: Spatially-separated heterodyne interferometer architecture is combined with monolithic glass construction techniques to provide a monolithic, spatially-separated, common-path interferometer. The monolithic interferometer includes multiple optical components bonded together into a monolithic structure. The bonded components provide both optics and structure for the interferometer, thereby producing a small, compact, and light-weight interferometry system. Beam splitters and combiners are provided on the interfaces between the optical components to direct and combine signal measurement, signal reference and local oscillator beams used in the interferometry system. The spatially-separated architecture reduces cyclic error values below those of polarization-separated interferometers. In addition, the monolithic architecture of the interferometer minimizes the impact of mechanical, thermal, and optical variations within the system.

Abstract: An InGaAs photodetector is provided having an avalanche photodiode (APD), a p-intrinsic-n (PIN) photodiode, and a microlens structure that provides high optical fill factors for both the APD and the PIN photodiodes. The photodetector can be used for both ranging and imaging applications, can be formed as a single pixel, and multiple pixels can be fabricated to form a focal plane array. A method of fabricating the photodiode is also provided.

Abstract: An X-ray examination apparatus includes a collimator unit (4) with a diaphragm (8) for limiting the X-ray beam (2), the circular aperture (31) of the diaphragm (8) having a first diameter for a first diaphragm and a second diameter for a second diaphragm setting. The collimator unit (4) also includes an X-ray filter (20) with detachable filter elements (21).