N. Djeu

Ultraviolet‐preionized discharge‐pumped lasers in XeF, KrF, and ArF

Lasers in XeF, KrF, and ArF have been excited in a uv‐preionized transverse electric discharge. Laser pulse energies exceeding 100 mJ with peak powers of several megawatts have been produced with electrical efficiencies of over 1%.

Efficient electric discharge lasers in XeF and KrF

Laser action has been obtained in XeF and KrF in a transverse electric discharge powered by a fast Blumlein‐type circuit. Over‐all efficiencies of these lasers exceeded 1% for XeF and 0.3% for KrF. Maximum pulse energies of 100 mJ in XeF and 30 mJ in KrF were extracted. In XeF the peak pulse power was 25 MW while in KrF the peak pulse power was 1.5 MW.

1‐μs laser pulses from XeF

Long‐pulse operation of the XeF laser has been achieved utilizing electron beam excitation of Ar/Xe/NF3 gas mixtures. For a total mixture pressure of 2.5 atm, ∼0.30 J of 350‐nm radiation was obtained in a 1‐μs FWHM pulse.

Efficient Raman conversion of XeF laser output in Ba vapor

Intense Raman emission at 585 nm has been observed from Ba vapor pumped by the XeF laser. Near‐unit photon conversion efficiency was measured.

Efficient blue emission from an intracavity-doubled 946-nm Nd:YAG laser

We report the first observation to our knowledge of coherent emission at 473 nm from an intracavity-doubled Nd:YAG microlaser. The d32 coefficient of potassium niobate was used in a 90-deg, temperature-tuned, Type I phase-matching configuration to generate the second harmonic of the 946-nm intracavity field. Output powers in excess of 5 mW at optical conversion efficiencies of approximately 2% have been observed with dye-laser pumping at 588 nm.

Raman beam cleanup of a severely aberrated pump laser

Distortion-free amplification of a diffraction-limited (D.L.) Stokes beam in a hydrogen Raman amplifier pumped by a severely aberrated XeCl laser (120 × D.L.) has been observed with an attendant power conversion efficiency of the order of 30 percent. The corresponding increase in available far field intensity over that from the aberrated pump beam is 5000. An optical integrator was used to focus the poor quality pump beam into the amplifier and to remove all near-axial components in the pump field. Numerical study of this process using a two-dimensional propagation code shows that the presence of near-axial pump components can cause phase matched four-wave mixing interactions with the Stokes, leading to increased angular divergence of the amplified Stokes beam and the development of secondary sidebands in the far field. When a moderately aberrated pump beam (20 × D.L.) was used, spatial sidebands of the Stokes beam were generated due to increased coherence length for the mixing process, significantly reducing the far field Stokes intensity.

Fiber-optic high temperature sensor

A crystalline structure, comprising an optical waveguiding region, a crystalline fluorescent temperature sensing region, and a crystalline junction between the optical waveguiding region and the crystalline fluorescent temperature sensing region. An embodiment of the present invention is a novel fiber-optic temperature sensor functional under high-temperature conditions. The fiber-optic temperature sensor comprises a continuous crystalline fiber optic high temperature sensor probe having a crystalline optical waveguiding region with first and second ends, and a crystalline fluorescent temperature sensing tip at one end thereof. The crystalline optical waveguiding region and the crystalline fluorescent temperature sensing tip are preferably crystallographically and thermomechanically compatible with each other. The fluorescent temperature sensing tip contains fluorescent ions that can be excited to fluoresce and produce a fluorescence emission. The fiber optic high temperature sensor probe also contains a crystalline junction preferably having a continuous, crystalline structure throughout. The crystalline junction is located between, and attached to, the crystalline fluorescent temperature sensing tip and the first end of the crystalline optical waveguiding region such that, preferably, a continuous, crystalline fiber optic high temperature sensor probe is formed.

Transverse electrodeless RF discharge excitation of high-pressure laser gas mixtures

Self-sustained discharge excitation of CO 2 , Xe, F, and HF laser transitions using a transverse electrodeless RF (TERF) configuration is investigated. Homogeneous long-duration excitation of high-pressure laser gas mixtures is demonstrated, and the operating characteristics associated with the four laser species in this discharge environment are explored.

Optically pumped cw Hg laser at 546.1 nm

cw laser oscillation has been achieved on the 546.1‐nm line in Hg I using an optical pumping scheme. The potentials of this laser are discussed.

DETERMINATION OF OPTICAL GAIN FOR CO TRANSITIONS IN A CS2–O2 FLAME BY OSCILLATION‐RANGE MEASUREMENTS

Optical gain in the neighborhood of 2% has been measured in CO vibration‐rotation transitions P(12)–P(14) in the bands 8–7, 9–8, and 10–9 in a free‐burning CS2–O2 flame. The flame was inside a single‐transition single‐mode CO laser cavity. Gain was determined from the change in the oscillation range of the frequency‐tuning curve. This method is particularly useful for the measurement of small optical gains and losses.