Labrum Optical Engineering

SAW/BAW Bragg cell

4,767,1988 - August 30, 1988

ABSTRACT: An acoustic signal is launched as a surface acoustic wave (SAW) by a hyperbolically tapered transducer and then reflected into a bulk acoustic wave (BAW) by a tapered reflector. At each frequency the tapered reflector must satisfy the phase match conditions between the SAW and BAW as defined by their wave vectors. Let k.sub.B be the projection of the BAW wave vector on the SAW. Then, if k.sub.G is defined to be the wave vector of the grid, ie., k.sub.G=2.pi./d, where d is the periodicity of the reflecting strips at the frequency under consideration, the phase match condition is k.sub.G=k.subB -k.sub.S. A reflector designed to satisfy this condition will reflect the SAW into a BAW at any desired angle (as specified by k.sub.B). The laser beam is then Bragg scattered by the Baw in the usual manner. The advantage of this scheme is that the tapered transducer separates the acoustic signals spatially so that no intermodulation products are formed. Furthermore, the tapered transducers are able to handle higher power levels than other transducers so hat high energy acoustic signals can, infact be used. An improvement in Bragg scattering signals can, infact be used. An additional improvement in Bragg scattering efficiency can be achieved by curving the reflective array in such a way as to direct the BAW so that the Bragg angle for optimum scattering efficiency is exactly met for all frequencies. This insures that the device can be used over a broad bandwidth without a fall off in the Bragg scattering efficiency.

Acousto-optic analyzer with dynamic signal compression

4,722,596 - February 2, 1988

ABSTRACT: An acousto-optic spectrum analyzer in which the dynamic range is effectively extended by detecting the frequency bands wherein the photo-detectors are saturated and providing a filter to suppress (attenuate) those frequencies. With this pre-filter, the entire amplitude of the spectrum appears to be within the dynamic range of the photo detectors. The actual spectrum can be reconstructed using the response of the suppression filter and the photo-detector (CCD) output.

Broadband optical processor for determination of frequency and time of arrival of multiple signals

4,712,059 - December 8, 1987

ABSTRACT: a real time processor for the detection and separation of multiple frequency hop signals and which is capable of determining both the frequency and time of arrival for all frequencies within the specified bandwidth.

Acousto-optic R-F receiver which is tunable and has adjustable bandwidth

4,696,061 - September 22, 1987

ABSTRACT: There is disclosed an acousto-optic filtering apparatus which includes Bragg cells in the signal path and in the local oscillator reference path of the apparatus in order to permit relatively high frequency signals to be detected by a relatively low frequency detector mechanism.

Photo-detector array with extended dynamic range for use in optical signal processing systems

4,648,135A - March 3, 1987

ABSTRACT: A signal handling system of improved dynamic range wherein a logarithmic circuit is interposed between the photo-diode array and other output circuitry.

Acousto-optical spectrum analyzer with expanded frequency resolution

4,636,718 - January 13, 1987

ABSTRACT: This invention is directed to a spectrum analyzer system which is laser-driven and which includes standard Bragg cell and standard photo-detector array as the output detector. In this system, the Bragg cell is driven by a bandwidth expansion circuit which receives the typical R.F. input signal, supplies it to a variable center frequency filter or to a bank of filters which then down-converts the signal and supplies the signal to a real time signal storage memory at a first signal rate. The signals are retrieved from the memory at a second, much greater signal rate, up-converted and supplied to the Bragg cell to effect the operation thereof in the usual fashion. This time based compression circuit has the effect of producing an improved optical spectrum analyzer with expanded frequency resolution.

Shutter system for stage-lighting spotlights

4,210,955 - July 1, 1980

ABSTRACT: A shutter system for stage lighting spotlights includes a housing having a fixed framing gate therein which has an opening there through for the passage of light. Two sets of opposing shutter blades are sandwiched, one on each side of the framing gate, between the framing gate and one of a pair of pressure plates which have means urging them toward the framing gate. Each shutter blade has a neck portion which extends through a slot in the housing and which serves as a handle in which pressure may be applied to move the shutter blade. The blades are normally held in place by the action of the pressure plates against the blades and framing gate.

Light-collecting reflector

4,151,584 - April 24, 1979

ABSTRACT: A light collecting reflector with a source of light comprises a main reflector having a central parabolic reflecting surface and an outer ellipsoidal reflecting surface surrounding the central surface. The main reflector is adapted to have a source of light placed along its central axis. A secondary reflector having a surface facing the reflector surfaces of the main reflector and having an open central portion to allow light to pass there through, is positioned in front of the main reflector so that light striking the reflector surface of the secondary reflector is reflected back toward the reflecting surfaces of the main reflector. The reflecting surface of the secondary reflector is accurate with radii that emanate from the circle with its concentric with the center axis of the main reflector.

Microscope system for observing Hi-Speed moving particles

4,136,950 - January 30, 1979

ABSTRACT: A microscope system for observing moving particles makes use of a television camera for producing a continuing series of images of such particles. A source of laser light pulses illuminate the particles with each pulse for a period short enough to stop their movement for the camera. The light source and camera are synchronized so that the light pulses occur only between the times that the camera produces image-information signals. For obtaining particle size measurements, a single light pulse during the time that the camera is not producing image-information signals is sufficient. For obtaining particle velocity measurements, two light pulses are required so that a double exposure occurs at the camera during a time that the camera is not producing image-information signals.

labrumopticaleng.com