Abstract: An apparatus for use in automatically correcting distortion in an optical signal includes an optical relay element positioned to receive the optical signal from a remote source and to relay the optical signal; and a photosensor positioned to receive a portion of the optical signal from the optical relay element, and configured to produce an electronic signal that varies with the distortion in the optical signal. Processing circuitry is configured to receive the electronic signal from the photosensor to detect variations in the electronic signal caused by the distortion in the optical signal, and to generate a control signal in response to the variations. An adjustment element is configured to receive the control signal from the processing circuitry and, in response to the control signal, to correct the distortion in the optical signal.

Abstract: A near-field scanning optical microscope uses short-circuit current or open-circuit voltage signals from a photosensor to generate and display an image of an object. The photosensor includes two pairs of Schottky-barrier contacts positioned on the photosensor's semiconductor surface along two orthogonal axes. Together the contact pairs define a gap, within which the object to be viewed is placed. When the microscope scans a beam of light over the gap, the photosensor produces two signals, each of which indicates the position of the light beam between one of the contact pairs. The microscope includes a computer that receives the signals from the photosensor during two scans, one conducted without the object on the surface of the photosensor (the “background” scan), and the other conducted with the object in place (the “object” scan).

Abstract: The invention employs a high-resolution semiconductor optical beam position sensor mechanically coupled to an optical beam source by a mechanical linkage which is either elastically deformable (in the case of a vibration sensor or accelerometer) or thermally expandable (in the case of a temperature sensor). The semiconductor optical beam position sensor is a planar semiconductor with a pair of electrodes thereon defining a gap therebetween. The optical beam has a uniform optical density or beam intensity which traverses within the inter-electrode gap. The two electrodes are two rectifying contacts on the surface of the semiconductor irradiated by the laser beam.