The United States of America As Represented by the Administrator of the

United States of America As Represented by the Administrator of Nasa

Other

Science Applications International Corporation

Science & Technology Corporation

Norman P Barnes

Mahendra G Jani

Keith E Murray

Ralph L Hutcheson

Brian M Walsh

Donald J Reichle

Clyde A Morrison

Milan R Kokta

George E Lockard

Elizabeth D Filer

Gregory S Herman

Waldo J Rodriguez

A method is provided for controlling second harmonic efficiency of laser beam interactions. A laser system generates two laser beams (e.g., a laser beam with two polarizations) for incidence on a nonlinear crystal having a preferred direction of propagation. Prior to incidence on the crystal, the beams are optically processed based on the crystal's beam separation characteristics to thereby control a position in the crystal along the preferred direction of propagation at which the beams interact.

Controlling second harmonic efficiency of laser beam interactions

A tunable laser includes dispersion optics for separating generated laser pulses into first and second wavelength pulses directed along first and second optical paths. First and second reflective mirrors are disposed in the first and second optical paths, respectively. The laser's output mirror is partially reflective and partially transmissive with respect to the first wavelength and the second wavelength in accordance with provided criteria. A first resonator length is defined between the output mirror and the first mirror, while a second resonator length is defined between the output mirror and the second mirror. The second resonator length is a function of the first resonator length.

Multiple-wavelength tunable laser

A coherent optical source, having a center frequency in the terahertz band can be generated. Two coherent optical sources of different frequencies can be mixed in a nonlinear crystal to generate an optical source having a third distinct frequency in the terahertz frequency range. The third frequency, an idler frequency, equals the difference between pump and signal wave frequencies incident on the crystal. The pump and signal wave frequencies are selected so that their frequency difference is in the terahertz range and so that the interaction between the pump, signal, and idler wave frequencies is phase matched using a cross-Reststrahlen band dispersion-compensated phasematching technique.

Method and apparatus for providing a coherent terahertz source

A method is provided to control the lasing wavelength of a laser material without changing or adjusting the mechanical components of a laser device. The rate at which the laser material is pumped with the pumping energy is controlled so that lasing occurs at one or more lasing wavelengths based on the rate. The lasing wavelengths are determined by transition lifetimes and/or energy transfer rates.

Method of controlling lasing wavelength(s)

A laser host material LuLF (LuLiF.sub.4) is doped with holmium (Ho) and thulium (Tm) to produce a new laser material that is capable of laser light production in the vicinity of 2 .mu.m. The material provides an advantage in efficiency over conventional Ho lasers because the LuLF host material allows for decreased threshold and upconversion over such hosts as YAG and YLF. The addition of Tm allows for pumping by commonly available GaAlAs laser diodes. For use with flashlamp pumping, erbium (Er) may be added as an additional dopant. For further upconversion reduction, the Tm can be eliminated and the Ho can be directly pumped.

Ho:LuLF and Ho:Tm:LuLF laser materials

A quasi four-level solid-state laser is provided. A laser crystal is disposed in a laser cavity. The laser crystal has a LuAG-based host material doped to a final concentration between about 2% and about 7% thulium (Tm) ions. For the more heavily doped final concentrations, the LuAG-based host material is a LuAG seed crystal doped with a small concentration of Tm ions. Laser diode arrays are disposed transversely to the laser crystal for energizing the Tm ions.

Quasi four-level Tm:LuAG laser

A room temperature solid-state laser is provided. A laser crystal is disposed in a laser cavity. The laser crystal has a LuAG host material doped with a concentration of about 0.35% Ho ions, about 5.57% Tm ions and at least about 1.01% Cr ions. A broadband energizing source such as a flashlamp is disposed transversely to the laser crystal to energize the Ho ions, Tm ions and Cr ions.

Flashlamp-pumped Ho:Tm:Cr:LuAG laser

The invention, a method and circuit for controlling the evolution time interval of a laser output pulse, comprises means for pumping a laser medium 13 in a resonator 10 that includes a Q-switch 22 and polarizer 26 that act in combination to control the loss in the resonator 10. A photodiode 11 senses the resulting fluorescence 12 which is applied to a two level Q-switch driver 27 the output of which selectively adjusts the level of loss in the Q-switch 22 and polarizer 26 from high to intermediate to substantially zero loss states to control the evolution time interval of the resulting laser output pulse.

Method and circuit for controlling the evolution time interval of a

The invention is a method and circuit for shaping laser pulses 17' in which a laser medium 12' in a laser resonator 10' that includes a Q-switch 14' and polarizer 13' which act in combination to control the loss of the resonator 10' and provide the laser output 17' representative of such loss. An optical diode 22' senses the level of the output pulse 17' and provides an output signal 23' that when amplified is used with a control voltage from a supply 29' provide a control signal 19' which is applied to Q-switch 14' to control the shape of the output pulse 17' by adjusting its length.

Growing community of inventors

Yorktown, VA, United States of America

Norman P Barnes