摘要:

A selective two‐step process is described for the photoionization ofF2centers. An electron trap density no greater than that of the originalF2center population is required for ∼100% ionization, and only modest light intensities are required (I∼10 W/cm2or less). Certain divalent transition‐metal ions have been found to make excellent traps. The two‐step process has allowed the production ofF+2center densities ∼1018/cm3, as needed for the construction of efficient lasers.

ISSN:0003-6951    

DOI:10.1063/1.90416

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Tunable dye‐laser emission has been obtained up to 12 850 A˚ by pumping a dimethyl sulfoxide solution of a carbocyanine dye with an Nd : YAG laser. The solution lased in two distinct wavelength ranges of 11 070–11 870 and 11 920–12 850 A˚ depending on the dye concentration.

ISSN:0003-6951    

DOI:10.1063/1.90417

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

A diffraction‐limited geodesic lens was demonstrated in a polyurethane film‐glass substrate waveguide structure. The lens has an aspherical depression and a rounded edge. The measured focal length remained at 10 mm up to 92% of the aperture. Diffraction‐limited focal spot size was measured for an input beam width of 2 mm. For larger input beamwidth, the spot size measurement was limited by the optical resolution of the detection system.

ISSN:0003-6951    

DOI:10.1063/1.90418

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

A single prism has been used to simultaneously couple light into and out of an optical waveguide, with a guiding length of 1 cm. The method, which is simple and reproducible, utilizes two optimized gaps for the coupling regions. Coupling efficiencies in excess of 90% have been achieved.

ISSN:0003-6951    

DOI:10.1063/1.90419

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Dichroic absorption can be produced by orientingMcenters in a NaF crystal. An optical waveguide adjustable polarizer is realized by using the NaF crystal as the top layer of a thin‐film glass waveguide. The measured polarization ratios as a function of the guide length are compared with the theoretical calculations.

ISSN:0003-6951    

DOI:10.1063/1.90420

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Using a tunable optical parametric oscillator, phase‐matched second‐harmonic generation was realized in high‐quality Ti‐diffused LiNbO3optical waveguides near the 1.08‐&mgr; fundamental wavelength. At 45 W peak power in 17‐mm‐long waveguides an efficiency for TM0→TE1conversion up to 25% was achieved. This value is three orders of magnitude larger than previously published results.

ISSN:0003-6951    

DOI:10.1063/1.90421

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

In then‐GaAs/Se=–Se=x–OH−/C liquid junction solar cell, modification of the semiconductor surface by incorporation of ruthenium increases both the fill factor and the open‐circuit voltage and improves the reproducibility of performance. The power conversion efficiency of the modified cell is 12% under ∼100 mW/cm2sunlight. Surface metal atoms or ions are shown to alter GaAs cell behavior widely; Ru represents a case for which the effect on cell performance is both positive and persisting.

ISSN:0003-6951    

DOI:10.1063/1.90422

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Efficient operation (5.0%) of the long‐pulse (0.5 &mgr;sec) XeCl laser is obtained by electron‐beam pumping of mixtures of neon, xenon, and HCl. Laser emission is observed at 308.0 and 308.2 nm. A small‐signal gain of 2.6% cm−1is measured from which the saturation intensity is calculated to be ∼0.35 MW cm−2and the optical absorption at the laser wavelength is calculated to be ∼0.26% cm−1. The electron‐beam‐pumped XeCl laser can be operated under static fill conditions with no measurable degradation in output power.

ISSN:0003-6951    

DOI:10.1063/1.90423

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

High‐pressure argon was excited by a 2‐ns 600‐keV e‐beam pulse, and time integrated as well as time resolved fluorescence spectra were measured. No significant dependence of line center (126.2±0.1 nm) or spectral width (80±10 nm) of the Ar2continuum on gas pressure was found in the range 0.5–20 bar. From the buildup time constant of fluorescence we calculated the three‐body rate constant for Ar2formation to be 5×10−33cm6/sec. The fluorescence decay was found to consist of two exponentials with time constants 8.6 and 39.2 ns at 20 bar and 12.6 and 73.9 ns at 10 bar, respectively. We attribute this behavior to the fluorescence originating from the singlet and triplet upper state. From the spectral shift between the two components we determined the singlet‐triplet splitting in the excited Ar2molecule to be 12 A˚ corresponding to 760 cm−1.

ISSN:0003-6951    

DOI:10.1063/1.90424

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Thin heteroepitaxial layers of InAs have been grown on (100) GaAs substrates and buffer layers by molecular beam deposition in a UHV chamber. Smooth epitaxial layers as indicated byinsituMEED patterns have been obtained at substrate temperatures in the range 330–530 °C and SEM micrographs and electron channeling patterns takenexsituhave confirmed these properties. MEED observations also indicated that epitaxial growth can be obtained at considerably lower deposition temperatures. InAs films, 0.5–2.0 &mgr;m thick, grown between 330 and 530 °C had bulklike electrical properties with residualn‐type carrier concentrations in the range 5×1016to 1×1018cm−3, the lowest values occurring for depositions at 530 °C.

ISSN:0003-6951    

DOI:10.1063/1.90425

出版商:AIP    

年代:1978

数据来源: AIP