Abstract: A multiple-pass laser amplifier that uses optical focusing between subsequent passes through a single gain medium so that a reproducibly stable beam size is achieved within the gain region. A confocal resonator or White Cell resonator is provided, including two or three curvilinearly shaped mirrors facing each other along a resonator axis and an optical gain medium positioned on the resonator axis between the mirrors (confocal resonator) or adjacent to one of the mirrors (White Cell). In a first embodiment, two mirrors, which may include adjacent lenses, are configured so that a light beam passing through the gain medium and incident on the first mirror is reflected by that mirror toward the second mirror in a direction approximately parallel to the resonator axis. A light beam translator, such as an optical flat of transparent material, is positioned to translate this light beam by a controllable amount toward or away from the resonator axis for each pass of the light beam through the translator.

Abstract: An optical Faraday isolator includes a slab of Faraday rotator medium coated to define input and output faces and internal reflective surfaces for causing the beam to travel between the input and output faces along a zig-zag path. Permanent magnets polarized in a direction normal to the plane defined by the zig-zag beam path are disposed on opposite sides of the beam path. The magnets are paired on each side with serially alternating polarity and the like poles are in transverse registration on opposite sides of the beam path to produce an intense, unidirectional magnetic field parallel to the beam path within the rotator slab. A quarterwave plate introduces a compensating amount of elliptical polarization to cancel unwanted elliptical polarization effects of the slab and its coatings. A beam shaving aperture at the exit of the slab shaves off divergent backward travelling rays.

Abstract: A seeded electro-optically Q-switches laser includes a pulser for pulsing the Q-switch within the seeded laser. The Q-switch pulser includes a pulse-shaping network having a saturable core inductor connected in series with the flow of current to the Q-switch for causing the developed pulse voltage waveform in Q-switch to have an initially reduced rate of change to reduce unwanted Fourier frequency components of the seed optical radiation in the optical resonator of the slave laser, whereby enhanced single-mode operation of the slave laser is obtained with reduced seed power.

Abstract: In a monolithic ring laser, the ring laser crystal is mounted in a monolithic heated support structure including a layer of solder which is readily softened by elevating the temperature of the heater to permit adjustment and readjustment of the optical alignment of the crystal. The monolithic crystal support includes a block of thermally insulative material interposed between the heating element and the surrounds for thermally isolating the heater and laser crystal from the surrounds.