Hughes Aircraft Company

Raytheon Company

Hughes Electronics Corporation

Eduard Gregor

Tzeng S Chen

Hans W Bruesselbach

James S Sorce

Mario P Palombo

Osher Kahan

Alexander R Muir

David W Mordaunt

Katherine V Strahm

A compact diode pumped laser including a nonuniform, single-or double-sided diode pumped laser head and a polarization output coupled (POC) resonator. The POC resonator employs reflections from two opposing uncrossed roof prism mirrors to produce a uniform near field and far field beam with diffraction or near diffraction limited quality. The single laser head particularly includes a laser rod, a sapphire envelope located about the rod, an area of antireflection coating located on the sapphire envelope between the rod and the diode array, and a high reflectivity nickel-plated indium layer located on the sapphire envelope on the surface thereof outside of the area of antireflection coating.

Compact diode pumped solid state laser

A conductively cooled flashlamp (30) for use solid state lasers. The flashlamp (30) has an elongated heat sink (31) with a reflective center channel (32), and a flashlamp tube (12) disposed in the channel (32) that extends beyond the ends of the channel (32). Heat conducting gaskets (37a, 37b) are disposed around respective ends of the envelope (34) that separate the tube (12) from the heat sink (31) to provide an air gap (35) therebetween. Clamps (36a, 36b) contact the gaskets (37a, 37b) and secure the envelope (34) to the heat sink (31). Electrodes (25a, 25b) of the tube (12) extend away from the ends of the tube (12) and heavy wires (38a, 38b) are connected to the electrodes (25a, 25b) and extend longitudinally away from the respective electrodes (25a, 25b). Heat conducting, electrically insulating heat sink members (41a, 41b) are disposed at opposite distal ends of the heat sink (31), and wire clamps (42a, 42b) secure the wires 38a, 38b to the heat sink members (41a, 41b). Thus, the tube (12) is disposed in close proximity to the reflective heat sink (31), which does not directly contact the tube (12). The tube (12) is clamped with good thermal contact to the heat sink near the electrodes where most of the heat is generated using indium gaskets (37a, 37b). The wires 38a, 38b that connect to the tube (12) are connected to the heat sink (31) with thermally conductive and electrically insulating material, such as beryllium oxide.

Laser head having a conductively cooled flashlamp

A compact diode pumped laser including a nonuniform, single- or double-sided diode pumped laser head and a polarization output coupled (POC) resonator. The POC resonator employs reflections from two opposing uncrossed roof prism mirrors to produce a uniform near field and far field beam with diffraction or near diffraction limited quality. The single laser head particularly includes a laser rod, a sapphire envelope located about the rod, an area of antireflection coating located on the sapphire envelope between the rod and the diode array, and a high reflectivity nickel-plated indium layer located on the sapphire envelope on the surface thereof outside of the area of antireflection coating.

A thermally conducting reflecting envelope for use in laser cavities, and laser apparatus employing such envelopes. A transparent heat conducting member, such as sapphire, surrounds a laser medium and has a transmissive coating thereon that transmits pump light provided by a pump light source onto the laser medium. The coating reflects the diode pump light and transmits laser light to suppress ASE that causes clamping of the laser output at a relatively low level. An absorbing elastic material is disposed on the dielectric coating and is adapted to absorb the laser light. Heat sinks are disposed in contact with the absorbing elastic material, and conducts heat away from the laser medium. A light entrance window or area is antireflection coated to transmit the pump light onto the laser medium. A liquid cooled version further includes a liquid cooling channel disposed between the laser medium and the thermally conducting member. Two slab lasers are also disclosed employing the present thermally conducting reflecting envelope. The present invention provides more efficient cooling and a more effective ASE suppression than conventional Samarium glass filters in solid state lasers pumped by flashlamps or laser diodes. The present invention provides for efficient heat conduction and removal from a laser medium, efficient transmission and absorption of laser light to suppress ASE, and efficient transmission of pump light to the laser medium.

Laser reflecting cavity with ASE suppression and heat removal

A Raman converter comprising an input optical pump beam (16) from a laser (18) that propagates through first and second Raman cells (12,24) and causes Stokes shifted waves (14,26) to be generated therein, and a polarizer (34) disposed between the Raman cells (12,24). The polarizer (34) is switchable during laser operation to cause the Stokes shifted waves (14) from the first Raman cell (12) to be circularly or linearly polarized, thereby causing the Stokes shifted waves (26) in the second Raman cell to be generated as rotationally shifted or vibrationally shifted waves respectively. The polarizer (34) may be switched to the selected circular or linear polarization, or may be repeatedly switched therebetween at regular or pseudo-random intervals. A second polarizer (32) may be disposed upstream of the first Raman cell (12) for selectively switching the polarization of the input pump beam (16) during laser operation. The polarizers (32) and (34) may each be used alone or in combination with each other. Combinations of rotational and vibrational Stokes shifted waves generated in the two Raman cells (12,24) provide multi-wavelength optical output signals with variable wavelength distributions.

Raman converter with variable wavelength distribution

A system and method for producing relatively square laser pulses derived from relatively Gaussian laser pulses. The system comprises a phase conjugate laser system that comprises a laser oscillator, an amplifying medium and a phase conjugate mirror having a nonlinear confined at a predetermined pressure. The mirror is adapted to truncate the front portion of an applied laser pulse. A plasma switch is disposed between the laser oscillator and the amplifying medium that has a gas confined therein at a predetermined pressure. The plasma switch and phase conjugate mirror cooperate to truncate the laser pulse to produce a laser pulse having a relatively square shape. Controlling the pressures in the plasma switch and phase conjugate mirror provides a means of controlling the formation of square-shaped laser pulses. In addition, a delay line may be employed in the system that is controllable in length that assists in controlling the truncation of the pulse in the plasma switch. A method of forming a square laser pulse in accordance with the invention comprises the following steps. A laser pulse is propagated through a plasma switch, and the pressure therein is adjusted to truncate the rear portion of the laser pulse. The truncated laser pulse is then transmitted through a laser amplifier medium to amplify the laser pulse. The amplified laser pulse is then reflected from a phase conjugate mirror. The pressure in the phase conjugate mirror is adjusted to a predetermined pressure to truncate the front portion of the laser pulse, thus producing a relatively square output pulse. Additionally, the relative length of a delay line disposed in the optical path may also be adjusted to assist in truncating the rear portion of the laser pulse.

Phase conjugate laser with a temporal square pulse

Apparatus and method are disclosed for providing a variable lens and birefringence compensator (10) adapted to be used within the resonator cavity of a repetitively pulsed, variable rate, solid state laser. A cylindrical body of optical material (12) having a temperature dependent index of refraction is thermally coupled to heat exchange means (14) surrounded by potting material (16) and a heat sink (18) which adds heat to or extracts heat from the exterior surface of the cylindrical body in order to establish radially dependent thermal and stress gradients within the body. The heat exchange means is supplied power through leads (20) from the same source (22) which excites the excitation mechanism of the solid state laser. Heat is infused into or extracted from the compensator body at the same rate at which the flashtube stimulates the laser rod (24) within the laser cavity defined by resonator mirrors (26, 28). The thermal gradient is used to create a dynamic lens of opposite power to that of the laser rod which corrects beam divergence in the lased output. The stress gradient causes the compensator body to behave like a birefringent substance. The double refracting behavior of the compensator effectively reconstructs the laser beam which passes through it which was depolarized by the birefringent action of the laser rod itself.

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Pacific Palisades, CA, United States of America

Eduard Gregor