Abstract: An adaptive optics system comprises a spatial light modulator, a beamsplitter, a pixelated spatial phase shifter, a beam combiner, an imaging device, and a processor. The spatial light modulator can modulate an incoming beam with an aberrated wavefront. The beamsplitter can receive the modulated beam and divide the modulated beam into a first beam and a second beam. The pixelated spatial phase shifter can spatially phase shift the second beam by at least two phases. The beam combiner can interfere the spatially phase shifted second beam with the first beam to form at least two interferograms on the imaging device, which can capture an image of the at least two interferograms in a single frame. The processor can determine the aberrated wavefront based on the at least two interferograms and provide one or more control signals to the spatial light modulator to mitigate aberrations in the aberrated wavefront.

Abstract: A spectrum analyzer device is provided having an optical “pixel” sensor array in a focal plane on a single chip, and a dedicated processor for each optical sensor that performs a pixel-based calculation of the power spectral density for the illumination captured by the optical sensor. Photoelectrons are maintained on the chip, thereby resulting in a significantly improved signal-to-noise ratio for the device. The device includes a sensor array having optical sensors arranged in a focal plane, where each optical sensor outputs a photon output signal upon receiving reflected illumination. The device also includes transform analysis units which receive the photon output signals from corresponding optical sensors and output power spectral density signals.

Abstract: A method of performing closed loop correction of phase aberrations, including the steps of directing an incoming light beam into a black fringe wavefront sensor via an adaptive optical device (“AOD”), dividing the incoming light beam into measurement and reference beams, altering the path length of the measurement beam and the location of the black fringe by modulating a ramp voltage of a modulator, combining the measurement and reference beams into a common output beam, detecting the black fringe in the common output beam using detectors mapped to the AOD, storing, as tagged ramp voltages, a corresponding ramp voltage for each detector when it detects black fringe, calculating phase errors based upon the tagged ramp voltages and modulator scaling, calculating adaptive optics correction voltages based upon the phase errors, transmitting and applying the correction voltages to the AOD to correct phase aberrations of the incoming light beam via phase conjugation.

Abstract: A heterodyne interferometer, adaptive optics system, method of measuring movement of a target and/or variations in a beam propagation medium, and method of controlling an adaptive optics system are provided. The heterodyne interferometer includes an acoustic-optical modulator that can superimpose a RF signal on a source signal, and output a zero order beam and a higher order beam. One of the beams comprises a target beam and the other beam comprises a local oscillator beam. A telescope can receive the target beam, and direct the target beam through the beam propagation medium to the target. A beam splitter can receive the local oscillator beam and the reflected beam from the target, and coherently combine the local oscillator beam and the reflected beam to produce a fringe pattern. A detector can receive the fringe pattern and generate an electrical beat signal, which can be demodulated based upon the RF signal.

Abstract: A fiber optic phased array, as well as associated methods and apparatus for controllably adjusting the frequency of the optical signals emitted by a fiber optic phased array, are provided that permit wide band phase control and may be implemented utilizing conventional analog electronics. In this regard, the method and apparatus can independently control the phase of the optical signals propagating through each fiber optic amplifier of the fiber optic phased array, even as large optical phase disturbances occur. As such, the control method and apparatus permit a fiber optic phased array to generate a flat phase front that, in turn, can provide a diffraction limited output laser beam. Alternatively, the control method and apparatus may be designed such that the output signals emitted by an array of fiber optic amplifiers has any other desired phase front, such as to compensate for atmospheric perturbations or the like.

Abstract: A fiber optic phased array, as well as associated methods and apparatus for controllably adjusting the frequency of the optical signals emitted by a fiber optic phased array, are provided that permit wide band phase control and may be implemented utilizing conventional analog electronics. In this regard, the method and apparatus can independently control the phase of the optical signals propagating through each fiber optic amplifier of the fiber optic phased array, even as large optical phase disturbances occur. As such, the control method and apparatus permit a fiber optic phased array to generate a flat phase front that, in turn, can provide a diffraction limited output laser beam. Alternatively, the control method and apparatus may be designed such that the output signals emitted by an array of fiber optic amplifiers has any other desired phase front, such as to compensate for atmospheric perturbations or the like.

Abstract: When a lightwave passes through a transmission grating, diffracted beams appear at the output or opposite side of the grating that are effectively Doppler shifted in frequency (phase) whereby a detector system can compare the phase of the zero order and higher order beams to obtain an indication of position. Multiple passes through the grating increase resolution for a given wavelength of a laser signal. The resolution can be improved further by using a smaller wavelength laser to generate the grating itself. Since the grating must only have a pitch sufficient to produce diffracted orders, inexpensive, ultraviolet wavelength lasers can be utilized and still obtain high resolution detection.

Abstract: An apparatus 10 and method for the recording and readout of multiple exposure holograms. For recording, the plane of polarization of the multiple pulsed linearly polarized laser beam 14 from source 12 is rotated by half-wave plate 26. Polarizing beam splitter 20 then divides the beam 14 into a test beam 24 and a recording reference beam 22. The test beam 24 is directed through a quarter-wave plate 28, through a test medium in chamber 34, reflected from mirror 36, back to beam splitter 20 and finally to film plate 37. On a first pulse, a first recording reference beam 22, 22' is directed through pockel cell 38, is reflected by beam splitter 40, through half-wave plate 76, off of mirror 42 and finally to film plate 37 to form a first hologram. On a second pulse a second recording reference beam 22, 22" is transmitted through beam splitter 40, reflected off mirror 48 and 50 and through half-wave plate 46, and finally directed toward film plate 37 forming a second hologram.

Abstract: A heterodyne phase-determining interferometer comprising a Smartt point diffraction interferometer (PDI) 10 in which the pinhole plate 22 is replaced by a half-wave, partially transmitting plate 22' with a pinhole 20 therein. The output beams 26 and 24 from the pinhole 20 are propagated through a frequency shifter 12 which includes a quarter-wave plate 28 whose axis is at 45.degree. to the polarization axes of the two beams 26 and 24 coming from the PDI 10, a half-wave plate 30 rotating at an angular frequency of .omega., and a linear polarizer which orients the polarization vectors of the two beams in the same direction along the propagation axis. The output of the frequency shifter 12 is a moving interference pattern consisting of alternate light and dark lines. This pattern is projected upon a phase-measuring means 14 comprising an array of photodetectors 34, 36 connected to a plurality of phase-to-voltage converters 38. There is one reference photodetector 34, the rest being test photodetectors.