Abstract: The present invention provides a free space optical communication system that uses orthogonal modes of aberration in a laser beam as means for encoding the information. The system comprises a transmission station which transmits the user defined information in terms of the amplitudes of certain orthogonal aberration modes present in the transmitted beam. The beam then travels through free space before it reaches the receiving station. The receiving station comprises a high speed wavefront sensor of light beams. The wavefront sensor measures the amplitudes of various orthogonal aberration modes present in the incident beam at different instants of time. The amplitudes of the orthogonal modes at a certain regular time interval are then used to extract the user information.

Abstract: A system and method for real-time monitoring of surface profile and thickness measurement of thin film using a grating array based wavefront sensor is disclosed. A laser beam is incident on a substrate on which deposition is to be performed and then a reflected beam from the substrate falls directly or after transmission falls on an array of gratings. The direction of a diffracted beam of a particular diffraction order is a function of the orientation and periodicity of the corresponding grating. The diffracted beam is made to pass through a combination of lenses to generate an array of focal spots. The surface profile of the incident laser beam is estimated from the displacements of these focal spots corresponding to the elements in the grating array. The grating array pattern can be altered to avail certain benefits such as simultaneous thickness and surface profiling, higher frame rate, flexible dynamic range and so on.

Abstract: The present invention provides a free space optical communication system that uses orthogonal modes of aberration in a laser beam as means for encoding the information. The system comprises a transmission station which transmits the user defined information in terms of the amplitudes of certain orthogonal aberration modes present in the transmitted beam. The beam then travels through free space before it reaches the receiving station. The receiving station comprises a high speed wavefront sensor of light beams. The wavefront sensor measures the amplitudes of various orthogonal aberration modes present in the incident beam at different instants of time. The amplitudes of the orthogonal modes at a certain regular time interval are then used to extract the user information.