Hughes Aircraft Company

Osher Kahan

Eduard Gregor

Laser apparatus comprising an integrating cavity, at least one lens and a heat sink arrangement that provides for a more uniform stored energy distribution, higher energy transfer efficiency and relaxed temperature control requirements. The laser apparatus incorporates a laser rod enclosed within a cavity. The cavity includes optically transparent heat sink means contiguous with and surrounding the laser rod. At least one laser diode array is disposed in a spaced relationship with respect to the axis of the rod. At least one lens is disposed between the diode array and the rod. The lens has a focal length and is disposed to focus light from the laser diode array onto the rod. The cavity is surrounded by reflective surfaces and is provided with at least one elongated aperture therethrough for passing light from the diode array into the interior of the reflecting cavity and onto the rod. The reflective surfaces reflect unabsorbed light passed through the rod for multiple passes through the laser rod.

Integrating laser diode pumped laser apparatus

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.

Variable lens and birefringence compensator

Apparatus and method are disclosed for providing an improved variable lens and birefringence compensator envisioned for use within the resonator cavity of a laser which is capable of continuous operation. A pair of cylindrical bodies of optical material (12A, B) having a temperature dependent index of refraction are thermally coupled to heat exchange means (14A, B) surrounded by potting material (16) which adds heat to or extracts heat from the exterior surfaces of the cylindrical bodies in order to establish radially dependent thermal and stress gradients within the bodies. The heat exchange means (14A, B) is supplied power through leads (20A, B) and infuses or removes heat in order to establish a thermal gradient which 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 passing through it which was depolarized by the birefringent action of the laser rod itself. The tandem arrangement (48) of variable lens and birefringence compensators is coordinated by temperature sensor and trigger means (66, 68) which sense the temperature of the compensators (50, 52) through thermocouples (60, 61) and which are coupled to heat exchange means (14A, B) via control means (70, 72) and leads (20A, 20B). The control means (70, 72) prevent the compensators from overheating and enable the lensing and compensating action to be maintained without interruption.

Variable lens and birefringence compensator for continuous operation

An improved laser rod cooling system in which a laser rod (18) is cooled by conducting the heat generated thereby to a flexible, cushioning gel (21) which surrounds and contacts the rod along its length and secures the rod within a fully enclosing support (22). The support is thermally conductive and transparent to the pumping energy from a flashlamp (12). The gel material absorbs differential thermal expansion between the rod and its support to avoid any stresses otherwise exerted on the rod, while the complete surrounding of the rod by the support minimizes thermal gradients within the rod. Thus, a light beam with minimal optical distortion is generated by the laser rod.

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Culver City, CA, United States of America

Osher Kahan