Abstract: Laser systems, exhibiting energy conversion efficiencies greater than 20%, employ divalent metal halides, dissociated either electrically or optically, and pumped optically, usually by means of an arc lamp or an incoherent flashlamp. Either pulsed and continuous-wave lasing can be effected in or near the visible region.

Abstract: A drive circuit supplies a semiconductor laser with current pulses corresponding to an input pulse signal. A current supply feeds a d.c. bias current to the laser. A monitoring photodiode produces a light detection signal indicative of the actual laser output level. The detection signal is supplied to a subtraction device, to which the pulse signal is also supplied via a low-pass filter. The subtraction device detects the difference between the two signals to produce an error signal. Integration devices produce average value signals, which are compared by comparators with reference voltages to obtain control signals. The current supply and the current drive circuit are responsive to these control signals to independently modulate the d.c. bias current and the amplitude of the drive pulses applied to the laser, whereby the laser output level can be stabilized to remain at a constant level.

Abstract: A control system for a dye laser is described, in which a pump pumps the dye from a supply vessel into a pressure vessel, in which there is an air pocket for damping vibrations, fluctuations in the pump delivery, etc. The dye passes out of the supply vessel as a jet via a nozzle. At least one sensor measures the dye filling level in the supply vessel and a control switches off the dye laser when the level in the supply vessel does not drop to the correct value after switching on the laser. The control system of the invention prevents the switching on of the laser if the level is too high or low before putting the laser into operation.

Abstract: A low divergence laser oscillator of the kind wherein an intra-cavity oscillator beam is propagated along a resonator axis and within a portion of the volume of the active medium and wherein a part of the intra-cavity oscillator beam intensity is coupled out of the oscillator by a first outcoupler as an extra-cavity beam. One of the oscillator beam is expanded and collimated so as to produce an expanded and collimated extra-cavity beam having a cross-sectional area substantially greater than the cross-sectional area of a portion of the active medium. Substantially the total intensity of the expanded collimated extra-cavity beam is introduced into the active medium so as to fill a volume of the active medium which is substantially greater than the volume of the above portion, thereby giving rise to amplification of the reintroduced beam. A polarizing element located within the resonator is used for the introducing.

Abstract: A laser frequency drift control device for an electrically powered, integral electrode and end-mirror, gas laser tube is disclosed. The control device includes a resistance and transistor heater assembly, which is electrically connected to be powered by the discharge current of the laser tube and thermally coupled to an end-mirror to heat the same, a thermal sensor coupled to the end-mirror to be heated for the purpose of obtaining temperature feedback, and a control circuit which varies heating of the end-mirror in accordance with the temperature feedback. LEDs provide visual feedback as to operation of the heater assembly to permit adjustment thereof. A method of controlling temperature variation induced laser frequency drift is also disclosed.

Abstract: A semiconductor laser array having a plurality of sets of interconnecting waveguides, each joining two optical waveguides together at respective branching junctions. The array has a plurality of semiconductor layers disposed on a substrate, at least one of the layers forming an active region for light wave generation and propagation under lasing conditions. One or more structures, such as current confining channels, a channelled substrate and variable thickness active region define a plurality of adjacent optical emitting waveguides. The waveguides are coupled together in a coupling geometry which ensures that breaks or failures in one or more branches are bypassed, thereby maintaining in-phase laser array operation.

Abstract: A semiconductor laser array having a single lobe far field intensity pattern radiating normal to the laser's light emitting facet. The laser array has a plurality of semiconductor layers disposed over a substrate, at least one of the layers forming an active region for lightwave generation and propagation under lasing conditions. A plurality of adjacent spaced apart optical waveguides defined by waveguides and interconnecting waveguides directly couples lightwaves propagating in each waveguide into an adjacent waveguide. The waveguides are characterized by separations which are not equal at the light emitting facet but are selectively varied so that the sampling function has only a single central lobe. In the preferred embodiment, separations are greatest for edge located and smallest for centrally located waveguides. Interconnecting waveguides connect adjacent waveguides at respective Y-shaped junctions, the junctions being symmetric at least on the output side of the laser.