Abstract: The present invention provides layered devices to control the spatial and spectral distribution of energy in optical beams, particularly high-intensity laser beams. These devices include improved versions of prior art thin-film (vacuum-deposited) interference filters, rugate structure anti-reflection coatings, Q-switches, pulse shapers, modulators, optical bistable devices and the like. Control is provided using materials with large second and third order susceptibilities to electric field polarization and, if necessary, means to apply appropriate electric fields.

Abstract: A system for generating a stable optical frequency from a laser signal having inherent frequency fluctuations. The signal from a injection-controlled pulsed laser is divided into two parts. One part is mixed with the signal from a stable CW laser to generate beat frequencies. These signals are amplified and recombined with the pulsed laser signal in an output modulator. In one embodiment, the difference frequency between the pulsed laser and the reference signal is less than 1000 MHz. The beat frequencies are increased by an X-band mixer to the microwave range where they can be readily amplified in an available broad band amplifier. In another embodiment, the transmitter laser and the reference laser operate at a different frequency in the micorwave range, say, above 5,000 MHz. The beat frequencies are obtained by a high frequency mixer such as a bulk crystal in a waveguide or cavity. In still another embodiment, two independent transmitter lasers generate pulses that occur with a significant time delay.

Abstract: A system for generating a stable optical frequency from a laser signal having inherent frequency fluctuations. The signal from an injection-controlled pulsed laser is divided into two parts. One part is mixed with the signal from a stable CW laser to generate beat frequencies. These signals are amplified and recombined with the pulsed laser signal in an output modulator. In one embodiement, the difference frequency between the pulsed laser and the reference signal is less than 1000 MHZ. The beat frequencies are increased by an X-band mixer to the microwave range where they can be readily amplified in an available broad band amplifier. In another embodiment, the transmitter laser and the reference laser operate at a difference frequency in the microwave range, say, above 5,000 MHZ. The beat frequencies are obtained by a high frequency mixer such as a bulk crystal in a waveguide or cavity. In still another embodiment, two independent transmitter lasers generate pulses that occur with a significant time delay.

Abstract: A femtosecond dye laser comprises a dye amplifier assembly (30) pumped by a mode-locked neodymium YAG laser (35) operating with frequency doubling. The main dye laser cavity as defined on one side of the amplifier assembly (30) by a linear prism structure (11 and 14) leading to an outlet mirror (15), and on the other side of the amplifier assembly by an assembly (20) constituting an anti-resonant mirror disposed about a saturable absorption device (40). An error signal is tapped by leakage from one of the mirrors (22) and is spectrally analyzed and compared with a reference wavelength (at 50) enabling a high tension amplifier (60) to be controlled to act on a piezo-electric stack (19) in order to fix the position of the outlet mirror (15) so as to adjust the optical length of the cavity as a function of the spectral characteristics of the pulses it produces.

Abstract: A semiconductor laser device in which the thickness of an active layer is made smaller than or equal to 0.04 .mu.m only in regions near the laser light emitting facets and the active layer in the other inner region is made to have a sufficient thickness not to cause a conspicuous deterioration in quality of the layer, that is, a thickness larger than 0.04 .mu.m.

Abstract: An optic sensing assembly for detecting reflection at a target area includes a cable holding element formed as an integral, one-piece body having sockets for directly receiving nonterminated ends of a light supply fiber optic cable and a light receiving fiber optic cable. Stop portions in the sockets accurately position the fiber optic cable ends. A housing has a cavity slideably receiving the holding element and latch structures on the holding element and housing engage with one another to secure the holding element with stop portions positioned at a precise location relative to housing. A strain relief structure is effective upon engagement of the latch structures for holding fiber optic cable ends within the sockets. An aperture in the housing communicates with the cavity for permitting light transmission between the cable ends and the target area. A lens structure formed integrally in the holding element directs or focuses light along paths from the cable ends to the target area.

Abstract: A semiconductor laser apparatus and housing are designed so that laser light leaving the housing through a window glass in the housing satisfies the following equation (3): ##EQU1## wherein d is the distance between the window glass and the laser light-emitting facet of the semiconductor laser device, .lambda.o is the oscillation wavelength of laser light, and .DELTA..lambda. is the space between the adjacent longitudinal modes.

Abstract: The gas laser with high-frequency excitation exhibits a laser tube (1), to which at least one pair of electrodes (5, 6) for the high-frequency excitation is externally fitted, and at least one inlet connection (2) and one outlet connection (3) for the gas. In order to permit a shorter distance between the pair of electrodes (5, 6) and the outlet connection (3), it is provided that a disc (12) having a high dielectric constant is disposed on the tube (1) between the pair of electrodes (5, 6) and the outlet connection (3), which disc extends substantially perpendicular to the axis of the tube.

Abstract: Discharge tube apparatus includes an outer containing vessel and a structure comprising for example five metal cylinders located co-axially within it. Each of the metal cylinders includes projecting spacers on its outer surface which serve to space it from adjacent ones. Such a structure is thermally insulating and may be arranged to enable a large temperature difference to be maintained between the interior of the discharge tube and the outer containing vessel. In other embodiments, a plurality of structures are included disposed along the axis of the tube. Also, dispenser segments for dispensing part of the active medium of a metal vapor laser may be included and arranged to shield vulnerable surfaces in the tube from direct exposure to the discharge.

Abstract: To generate a laser beam of significantly higher quality and high output power without damaging the output coupler (mirror), a novel stable optical laser resonator includes, in particular, a retro-reflector having an aspherical concave mirror for correcting intracavity wavefront aberrations induced when the laser beam travels through the lasing medium. The optimal surface constants of the geometry of the aspherical mirror are determined by an optical interferometry technique, an geometrical ray-tracing technique, and computer-aided ray tracing technique.

Abstract: A method for recycling laser flashlamp radiation in selected wavelength ranges to decrease thermal loading of the solid state laser matrix while substantially maintaining the pumping efficiency of the flashlamp.

Abstract: A laser fluid control apparatus and method provide selective, precise control of the fluid supplied to the laser. The flow of the fluid to the laser can be automatically adjusted according to a selected, programmed control to provide a high volume of the fluid to the laser during initial operation of the laser for a quick warm-up of the laser and a reduced volume after the laser has warmed-up for more economical operation of the laser. Different fluid mixes can also be provided for enhancing laser performance. A control for pulsed or continuous wave laser operation can be actuated to automatically change the composition of the fluid supplied to the laser for continuous wave laser operation as compared to that for pulsed operation.

Abstract: A laser temperature controller is disclosed for controlling the temperature of a laser device. The controller includes a bridge circuit connected to a thermistor device which is mounted on the laser package. The bridge circuit generates error signals representing a need for cooling or heating as the operating temperature of the laser rises or falls about a set threshold. A voltage conversion circuit converts the error signals to a positive or negative polarity voltage. The output of the voltage conversion circuit is applied to a pair of operational amplifiers which input the voltage and compare it to a set reference voltage. When cooling is required a first amplifier provides a biasing voltage to a transistor when a set threshold is exceeded. The associated transistor switches drive current to a thermoelectric device mounted on the laser package thereby, cooling the laser.