Method and apparatus for providing a large fraction of the energy coupling from an unstable resonator in the central lobe of the far field pattern of the output beam from the resonator are disclosed. The resonator is designed to allow a low order mode pattern to resonate about the optical axis therethrough and radiation is coupled out from both the axial region and the outer region of the mode. The geometry of the systems is formed with transmissive and reflective optics in various configuration...

A laser device having an improved resonator utilizes a single rigid base component for a light reflector coating that defines and forms the end terminals of the resonator cavity, means being provided for translating and reflecting the laser beam between linear light paths that respectively terminate at the mirror surfaces provided by the coating. Various embodiments are shown and in which one or more prisms are used to fold the laser beam between offset and parallel light paths. The end terminal...

A resonator feedback system is disclosed wherein the output from a resonator having adaptive optics is monitored by a detector within a feedback loop to provide electrical control signals to actuators attached to the adaptive optics to control the phase of the radiation within the resonator to produce an output beam having a near diffraction limited distribution. In one embodiment, a portion of the output beam is phase modulated at discrete frequencies and focused through an aperture onto a dete...

The high power laser includes a high gain medium (>80%) such as a lightly doped Nd:YAG rod contained within an unstable optical resonator of the type wherein power flows outward from the optical axis of the resonator. The output beam is coupled out of the resonator by means of a coupling device having a high coupling factor (>55% of the circulating power inside the optical resonator) and in a preferred embodiment the coupling factor is as high as 80-90%. The optical resonator is preferably...

In one application, the apparatus is used with unstable laser resonators which include a gain region defined by a concave mirror and a convex mirror. The apparatus includes a spectral line selection medium, such as a multiple band pass filter or a multiple diffraction grating, which is located so that the laser beam directed out of the laser gain region impinges thereon. A retroreflector is positioned so that the spectral lines selected by the line selection medium are reflected back into the la...

An electro-optic diffraction grating tuned laser comprising a laser medium, utput mirror, retro-reflective grating and an electro-optic diffraction grating beam deflector positioned between the laser medium and the reflective diffraction grating. An optional angle multiplier may be used between the electro-optic diffraction grating and the reflective grating.

The depletion of energy stored in the transfer gas component of a low pressure, short pulse laser system following excitation of the laser gas medium consisting of a lasing gas component and a transfer gas component is achieved by extracting a plurality of output pulses by providing a sufficient delay between output pulses to permit the transfer of energy from the transfer gas component to the lasing gas component.

In a high power laser, such as one employing a relatively high gain lasing medium such as CO.sub.2 or Nd:YAG, the optical resonator for the laser comprises a positive branch unstable resonator. The output beam is coupled from the unstable resonator by means of a partially transmissive mirror of the resonator, whereby a filled-in beam is obtained while facilitating optical alignment of the output coupling means. In a preferred embodiment, the optical resonator comprises a pair of mirrors collinea...

An unstable resonator to be used in high power, narrow line CO.sub.2 pump lasers comprises an array of four reflectors in a ring configuration wherein spherical and planar wavefronts are separated from each other along separate optical paths and only the planar wavefronts are impinged on a plane grating for line tuning. The reflector array comprises a concave mirror for reflecting incident spherical waves as plane waves along an output axis to form an output beam. A plane grating on the output a...

A waveguide gas laser is disclosed excited with bursts of a transverse rf electric field at a frequency ranging from about 30 MHz to about 3 GHz. The bursts have a duration ranging from about 0.1 .mu.sec. to about 10 .mu.sec. and a repetition rate ranging from about 500 Hz to about 100 kHz. This excitation is sufficiently rapid to produce gain switching in the laser gas, resulting in high peak power, short duration, single-line laser output pulses.