摘要:

Recently, there has been considerable interest in the use of single‐mode diode lasers in atomic frequency standards. In the present paper theoretical calculations are performed in order to quantify the expected performance improvement upon incorporation of diode lasers in rubidium gas cell atomic frequency standards. We assume that clock signal shot noise, the diode laser’s quantum noise, and diode laser frequency locking noise all contribute to the atomic frequency standard’s stability. Our results indicate that white‐noise Allan variances of ∼6×10−15/(&tgr;)1/2are possible if enhanced cavityQdiode lasers are employed, whereas for presently available commercial diode lasers we predict white‐noise Allan variances of ∼3×10−14/(&tgr;)1/2. These variances represent a 2–3 orders of magnitude improvement in frequency stability over that currently obtained with rubidium gas cell atomic clocks.

ISSN:0021-8979    

DOI:10.1063/1.336847

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Near‐field optical‐scanning (NFOS) microscopy or ‘‘optical stethoscopy’’ provides images with resolution in the 20‐nm range, i.e., a very small fraction of an optical wavelength. Scan images of metal films with fine structures presented in this paper convincingly demonstrate this resolution capability. Design of an NFOS microscope with tunnel distance regulation, its theoretical background, application potential, and limitations are discussed.

ISSN:0021-8979    

DOI:10.1063/1.336848

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The use of a piezoelectric crystal as the substrate for a photoresist film provides unique resist characterization capabilities. In particular, the photoresist near the substrate is probed in real time. The basis of this measurement technique is described, emphasizing the physical phenomena responsible for observed piezoelectric crystal response behavior. Demonstration of this analysis to a gelatin‐based resist is given. The influence of solvent drying is readily distinguishable from the effects of photohardening reactions.

ISSN:0021-8979    

DOI:10.1063/1.336849

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Dark‐field images are observed with a stigmatic (immersion objective lens) secondary ion mass spectroscopic ion microscope by means of an eccentric objective aperture, and are a useful extension of shadow contrast imaging. The spatial resolution in these images is comparable with conventional bright‐field imaging, provided that a narrow energy bandpass is selected to minimize chromatic aberrations. It is demonstrated that the dark‐field method is useful for correlating surface relief with chemical contrast in the compositional secondary ion mass spectroscopic mapping of conventional ion microscopy. Further, based on the information acquired in the dark‐field imaging mode, digital techniques to compensate for asperity artifacts in conventional ion microscopy are proposed.

ISSN:0021-8979    

DOI:10.1063/1.337021

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The usefulness of optothermal spectroscopy for quantitative analysis is discussed. It is shown theoretically and experimentally that optothermal spectroscopy is comparable to ordinary transmission spectroscopy for the determination of optical absorption coefficients.

ISSN:0021-8979    

DOI:10.1063/1.336796

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

A novel kind of doubly resonant light scattering involving the Floquet–Bloch waves of a fine‐period stratified structure is discussed. These waves can be Bragg scattered by a weak coarse‐period superlattice provided a certain Bragg‐like resonant condition is satisfied. Included among the unique properties of this kind of scattering are wavelength selective wide‐angle beam deflection by acoustic waves in the 10 MHz–1 GHz range, the ability to enhance or impair the efficiency of Bragg reflection by a conventional fine‐period grating, and, in one particular case, very wide‐band modulation of light. Coupled‐wave equations describing this interaction are solved for a variety of different geometries, and some potential applications proposed.

ISSN:0021-8979    

DOI:10.1063/1.336797

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

Polarizers and retarders have long been known as the basic building blocks of Lyot and Solc filters. Recently the use of an optically active medium along with polarizers and retarders has been found to be useful for modifying the transmission characteristics of the birefringent filter system. In this paper, the effect of using an optically active medium as the interstage element of a Solc filter has been studied. The idea of a birefringent band suppression filter has been found and the tuning procedures of these fixed‐type filters have also been discussed.

ISSN:0021-8979    

DOI:10.1063/1.336798

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

A new model for phase conjugate mirror reflectivity is derived and applied to a laser cavity with phase conjugate mirror. We find that by matching the phases of transverse cavity and phase conjugate mirror modes, the phase aberration correction ability of the mirror can be significantly improved.

ISSN:0021-8979    

DOI:10.1063/1.336799

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The steady‐state space‐charge field and the response time of a photorefractive material illuminated with a sinusoidal interference pattern are derived for two models in which both electron and hole transport are important. In the first model in which electrons and holes are produced from a single set of recombination centers, the sign of the steady‐state space‐charge field depends on the relative value of the conductivities and/or absorption coefficients of the electrons and holes, and a single response time proportional to irradiance is obtained. In the second model in which electrons are photoionized from one set of recombination centers and holes from another, the sign of the space‐charge field depends on the relative concentrations of the empty hole and electron traps, and two time constants, each inversely proportional to irradiance, are obtained.

ISSN:0021-8979    

DOI:10.1063/1.336800

出版商:AIP    

年代:1986

数据来源: AIP

摘要:

The surface impedance of a plastic foam with high flow resistance has been measured with a new method at acoustical frequencies. The Biot theory provides a description of the behavior of this surface impedance from the contributions of the fast and the slow compressional waves to pressure and acoustical velocity at the surface of the foam. The contribution of the slow wave can be observed in spite of its strong damping.

ISSN:0021-8979    

DOI:10.1063/1.336801

出版商:AIP    

年代:1986

数据来源: AIP