摘要:

The variation of the refractive index of an unclad fused silica fiber and the preform from which it was pulled was determined over the wavelength range 0.5–1.1 &mgr;m, in 0.025‐&mgr;m steps. The index is determined from an analysis of the backscattered radiation produced when light from an appropriately filtered xenon‐arc source impinges transversely upon the fiber or preform. The variation of the index of refraction of the fiber follows those of the preform and published values for bulk fused silica material to within 2 parts in 10−4, with the exception of two points at 0.65 and 0.95 &mgr;m.

ISSN:0003-6951    

DOI:10.1063/1.1655244

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

Experiments on light propagation and electro‐optic modulation have been made for poled LiNbO3single‐crystal thin films fabricated by the method of epitaxial growth by melting (EGM). The values of the refractive indices are found to beno= 2.200 andne= 2.184. A phase modulation experiment has been carried out using a Mach‐Zehnder interferometer in the region of 100 Hz‐3 MHz. The electro‐optic coefficients of the film have been determined by the phase‐compensation method, and the values obtained arer33=12 andr13=2.3×10−12m/V.

ISSN:0003-6951    

DOI:10.1063/1.1655245

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

We report efficient up‐conversion of low‐level ir radiation near 10 &mgr; to the near ultraviolet. Radiation at 9.26 &mgr; is converted to 3305 Å with a photon conversion efficiency of 58% and a corresponding power gain of 16.2. The process employs resonant two‐photon pumping of the nonallowed 3s‐3dtransition in Na.

ISSN:0003-6951    

DOI:10.1063/1.1655246

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

A new electric‐field‐actuated optical switch capable of wide‐angle deflection is described. The switch element makes use of the high angular selectivity of thick Bragg gratings and can be fabricated both in bulk and in thin‐film configurations. Experimental verification of the switch action in a bulk configuration is presentd. Modulation of 35% was observed in this first observation of the effect.

ISSN:0003-6951    

DOI:10.1063/1.1655247

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

Optically pumped laser oscillation has been obtained in vapor‐grown epitaxial GaAs mesa structures which have verticalas‐growncrystalline facets furnishing the optical feedback.

ISSN:0003-6951    

DOI:10.1063/1.1655248

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

If a GaAs diode is biased above threshold and if the dopingNexceeds a critical valueNpof about 1021m−3, the instability due to negative differential conductivity (NDC) can settle into a stationary anode layer. This layer remains when the voltage is subsequently reduced below threshold, provided thatNis sufficiently uniform near the anode. A diode in which the doping or the cross section increases toward the anode exhibits static negative differential resistance. When a diode with a small anode overdoping is biased above threshold, a depletion layer forms at the anode and, ifN>Np, propagates towards the cathode. The simulation of negative conductance at 50 GHz in the LSA mode raises the possibility of high‐efficiency amplification at very high frequencies by parastable diodes.

ISSN:0003-6951    

DOI:10.1063/1.1655249

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

Aluminum was implanted in ZnSe at 90 keV to a dose of 1015ions/cm2at room temperature. Hall‐effect and sheet‐resistivity measurements were made on the samples for various annealing conditions. The implanted layer is found to be degeneraten‐type having a sheet resistivity of ∼103&OHgr;/□, after annealing at 900°C for 4 h.

ISSN:0003-6951    

DOI:10.1063/1.1655250

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

A comparison was made between low‐energy ion backscattering and Auger electron spectroscopy (AES) in the analysis of various coverages of sulfur on a nickel (111) crystal plane. For the intensity ratios S/Ni a linear relationship between both techniques was found for submonolayer coverage. Using the calibration of Perdereau for AES, ion scattering intensities are calibrated and relative values are obtained for the neutralization probabilities of Ne+and He+scattered from Ni and S. For 1‐keV Ne+ions neutralization is about a factor of 7 lower for scattering from S than from Ni. Ion scattering is more sensitive to the position of adsorbed atoms than AES; a shadowing effect shows that the S atoms sit on top of the Ni surface layer. Both effects result in a high sensitivity of Ne+scattering for adsorbates such as S or O, the detection limit being some 10−4of a monolayer.

ISSN:0003-6951    

DOI:10.1063/1.1655251

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

Epitaxial films of the highly conducting organic charge‐transfer salt tetrathiafulvalinium tetracyanoquinodimethanide, (TTF) (TCNQ), grown on NaCl substrates were analyzed using electron diffraction and electron and polarized optical microscopy techniques. The films were found to orient with the high‐conductivity (TTF) (TCNQ)baxis along [110] directions of the NaCl. Preliminary optical, infrared, and electrical data obtained on these films are also presented.

ISSN:0003-6951    

DOI:10.1063/1.1655252

出版商:AIP    

年代:1974

数据来源: AIP

摘要:

Magnetic bubble and ring domains are generated in LPE garnet films by locally exciting spin precession near the ferrimagentic resonance frequency at high microwave power densities. Due to the spin precession, radial and azimuthal forces act on the bubbles. The radii of the ring domains vary with the microwave power and the bias field. The stability range of these domains extends over a bias field range of about 0.18 times 4&pgr;Ms. The dynamic behavior of the ring domains could be studied by amplitude modulation of the microwaves.

ISSN:0003-6951    

DOI:10.1063/1.1655253

出版商:AIP    

年代:1974

数据来源: AIP