摘要:

The observation of a new effect, the photoinduced Rayleigh light scattering, (the PIRLS) was found in BaTiO3. This scattering has the two following features: it exists simultaneously with a bulk photovoltaic effect in BaTiO3and it is an example of dynamic (but noncritical) scattering process. The main purpose of this letter is to describe the possible micromechanism responsible for the observed dynamic scattering close to the ferroelectric‐paraelectric phase transition in BaTiO3.

ISSN:0003-6951    

DOI:10.1063/1.89909

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

We have measured a 0.1% modulation of electron current in a lead tin selenide film due to a bulk acoustic wave propagated in the barium fluoride substrate. This effect was observed as an ac component of the current at the acoustic frequency 0.6 MHz.

ISSN:0003-6951    

DOI:10.1063/1.89910

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

A simple coupled‐mode theory has been developed for acoustic‐surface‐wave wedge transducers. Surface‐wave transducers have been fabricated to operate on aluminum using water as the wedge material. The measured efficiency was 68% at 2.75 MHz, the theoretical value being 81%. Transducers have also been fabricated to operate on glass with a rubbery solid, RTV 615, as the wedge material. The experimental and theoretical efficiencies of this transducer at 3.2 MHz were 35 and 50%, respectively. The surface‐wave leakage coefficient of RTV 615 on glass has been measured and found to be in excellent agreement with theory.

ISSN:0003-6951    

DOI:10.1063/1.89911

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

The sensitivity of a miniature glow discharge tube to electromagnetic millimeter‐wave radiation (70 GHz) was investigated in magnetic fields near the cyclotron resonance. A 100‐fold increase in the signal‐to‐noise ratio (SNR) was obtained at the cyclotron resonance. The SNR of the tube at cyclotron resonance was greater than ten times that of a commonly used crystal detector for millimeter‐wave radiation (1N53D) measured under similar conditions.

ISSN:0003-6951    

DOI:10.1063/1.89894

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

The polarization dependence of the ion expansion from the front and rear of laser‐irradiated thin‐film targets is measured. The thermal ion component shows an increased asymmetry with incidentppolarization compared withs‐polarized radiation. This is attributed to reduced thermal conductivity. Various possible mechanisms for this effect are discussed.

ISSN:0003-6951    

DOI:10.1063/1.89912

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

In this letter we discuss the stability criteria in recombination‐ and attachment‐dominated metal vapor laser discharges. The mercury halide laser discharges are typical of attachment‐dominated discharges, while the metal vapor exciplex lasers, like CdHg*, are typical of recombination‐dominated discharges. In high‐power electronic transition laser discharges, a relatively large excited‐state population exists which dominates the stability of these discharges. This occurs because the excited states have a smaller ionization potential and larger ionization cross section than the ground state. As a result, multistep ionization is the dominant ionization. When three‐step ionization is dominant and electron mixing of the excited states is unimportant, attachment‐dominated discharges will be stable if the attachment rate &bgr;⩾m&ngr;i0, where 2<m⩾3 and &ngr;i0, is the equilibrium ionization rate. For a recombination‐dominated discharge the criterion in this limit isane0⩾m&ngr;i0where 1.0<m⩾1.5 andais the recombination coefficient andne0is the equilibrium electron density.

ISSN:0003-6951    

DOI:10.1063/1.89913

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

High‐efficiency secondary electron emission due to incident ions was obtained from a porous MgO‐Ag layer prepared from a suspension of MgO, MgCO3powder, and Ag paste. Field‐dependent secondary emission yield larger than unity was achieved under relatively low‐energy ion bombardment. The introduction of Ag produces a uniform surface potential and therefore results in a stable secondary emission current. This type of emitter is potentially useful for application in gas‐discharge devices.

ISSN:0003-6951    

DOI:10.1063/1.89914

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Electrical conductivity caused by photoelectron emission from ultrafine particles suspended in a gas has been observed; one obtains information on the concentration as well as on the size of the particles. Furthermore, some bulk and surface properties of small particles not in contact with any substrate can be investigated at any temperature via the photoelectric threshold and the yield of photoelectrons. The method is extremely sensitive, i.e., measurements can be made at a very low particle concentration (∼103cm−3) and small particle radii (<50 A˚).

ISSN:0003-6951    

DOI:10.1063/1.89915

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

A new class of room‐temperature infrared detectors, which exploits the photocapacitive effect in MIS and MISIM devices, is reported. An (unoptimized) peak detectivity of ∼3×1012W−1 cm Hz1/2has been measured in a prototype Si device.

ISSN:0003-6951    

DOI:10.1063/1.89895

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Argon bubble formation has been observed by Rutherford backscattering spectrometry and cross‐sectional transmission electron microscopy in PtSi sputtered by Ar ions of 20–160 keV. The backscattering data show the bubble formation process to be repetitive. This phenomenon is interpreted in terms of Ar release due to the sputter etching.

ISSN:0003-6951    

DOI:10.1063/1.89896

出版商:AIP    

年代:1978

数据来源: AIP