摘要:

Measurements of spark source emission, transmission, and photoionization spectra in a CO2laser mixture seeded with a low‐ionization‐threshold additive are presented. The results show a photoelectron density enhancement in excess of 3 orders of magnitude contained within a narrow transmission band at 1200 A˚. Enhancement is also observed at wavelengths between 1700 and 2100 A˚. The long‐wavelength effect, characterized by an increased photon mean free path, may identify a two‐step photoionization process.

ISSN:0003-6951    

DOI:10.1063/1.88988

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

Efficient wide‐band high‐power generation of CO2laser second‐harmonic radiation is reported using a ’’stack‐of‐plates’’ approach to phase match the interaction in GaAs. A long collinear interaction length is achieved by using a series of {111} GaAs crystalline plates at Brewster’s angle, each one coherence length thick, oriented so as to alternate the sign of the nonlinear polarization in each consecutive plate. The peak second‐harmonic power generated was 60 kW at 5.3 &mgr;m using 3 MW of mode‐locked pump power with a stack of 12 GaAs plates. 420

ISSN:0003-6951    

DOI:10.1063/1.88989

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

We have demonstrated pulsed distributed‐feedback laser action in KCl:Li containing FA(II) color centers with spatially modulated concentrations. Laser outputs at various wavelengths between 2.6 and 2.8 &mgr;m have been observed with linewidths narrower than 0.2 nm. The absorbed pump power at threshold was 1.5 kW, and efficiencies of up to 6.7% were measured.

ISSN:0003-6951    

DOI:10.1063/1.88990

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

X‐ray and electron beam diffraction analyses have been carried out on thin films deposited from a beam of carbon ions. Results show that the films consist of a polycrystalline background of cubic diamond with a particle size of 50–100 A˚ with single‐crystal regions up to 5 &mgr;m in diameter.

ISSN:0003-6951    

DOI:10.1063/1.88963

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

We report the preparation of a polycrystalline thin‐film InP/CdS solar cell of area 0.52 mm2having a power conversion efficiency of 2.8% under AM1 conditions. Based on the current‐voltage characteristics, we estimate that development of an improved contact to thep‐type InP would result in substantially higher efficiencies without any further improvement in the InP/CdS interface.

ISSN:0003-6951    

DOI:10.1063/1.88964

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

A dc‐to‐rf conversion efficiency of 37% combined with an output power of 3.4 W at 3.3 GHz has been obtained from a Schottky‐barrier GaAs IMPATT diode having a lo‐hi‐lo profile. The donor spike or clump was produced by implanting silicon into an epitaxial layer with an‐type concentration of 1.65×1015cm−3. Pyrolytic Si3N4was used to encapsulate the GaAs during the postimplantation anneal. For these devices, the Si3N4deposition procedure was found to be critical and had to be optimizied to achieve reproducible results. The devices have had very uniform electrical characteristics, and a large yield of devices with greater than 30% efficiency has been obtained. These results indicate that implantation can be used to produce lo‐hi‐lo IMPATT’s with significantly higher device yields than have been obtained by epitaxial techniques.

ISSN:0003-6951    

DOI:10.1063/1.88965

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

The surface photovoltage technique has been employed to measure the hole diffusion length on threen‐type InP specimens. The hole diffusion length was found to be 1.8 &mgr;m for specimens with (111) orientation and 1.4 &mgr;m for specimens with (100) orientation. The measured hole diffusion length was found to be independent of the surface conditions.

ISSN:0003-6951    

DOI:10.1063/1.88966

出版商:AIP    

年代:1976

数据来源: AIP

摘要:

We report successful fabrication of continuous, flexible, and high‐strength (1600 MN/m2) composite filaments of Nb3Ge (Tc18 °K) and Nb3Sn, involving chemical vapor deposition of these compounds on Nb‐coated high‐strength W–1% ThO2filaments.

ISSN:0003-6951    

DOI:10.1063/1.88967

出版商:AIP    

年代:1976

数据来源: AIP