摘要:

Electro‐optic switching has successfully been demonstrated on untwinned (010) epitaxial bismuth titanate films grown on (110) MgAl2O4substrates. This result is achieved on large‐area films using an interdigitated electrode array structure which can be used both for electrical poling and subsequent electro‐optic address. A contrast ratio higher than 7:1 between the on and off states is obtained with a 10‐&mgr;m‐thick film. A gradual variation of the contrast ratio with switching field is observed, which gives the film a capability for grey scale.

ISSN:0003-6951    

DOI:10.1063/1.1654459

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

This letter reports a theoretical and experimental investigation on the effect of placing a thin Permalloy layer atop bubble‐domain materials. The Permalloy layer shifts and broadens the domain static bias field range because of the increase of bubble energy. The bias field shift effect starts diminishing in the presence of an in‐plane field. The experimental observations are satisfactorily explained by an analytical model in which the magnetostatic coupling energy between Permalloy and bubble is first calculated and then extended to Thiele's stability theory by a pertubation method.

ISSN:0003-6951    

DOI:10.1063/1.1654460

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

When the focused beams of a pulsed CO2laser and a cw CO2laser were superimposed, the pulsed gas breakdown threshold was raised. It was found that the increase in the threshold was dependent on the gas pressure and cw power. When the intensities obtained with different focal diameters were compared, it was found that the cw gas breakdown threshold has a 1/r2dependence on the radius of the focused cw power spot.

ISSN:0003-6951    

DOI:10.1063/1.1654462

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

The threshold for laser‐induced gas breakdown at 10.6 &mgr;m has been investigated in the presence of a spark discharge. Lowering of the threshold was observed over that measured in the absence of the spark for several gases. In argon at 100 Torr, threshold was a factor of 3.9 lower with the spark 3.7 cm from the laser‐induced breakdown region.

ISSN:0003-6951    

DOI:10.1063/1.1654463

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

The photocount autocorrelation of non‐Gaussian scattered laser light is discussed as a tool for the study of both very dilute or highly correlated scattering systems. A scaled photocount correlation technique is introduced and shown to produce a function directly proportional to the correlation function of the integrated scattered intensity, independent of the field statistics. This technique overcomes the serious problems of interpretation that can arise when the commonly used clipped correlation technique is applied to non‐Gaussian fields. The scaled correlation technique is demonstrated experimentally with a simple scattering system, a small number of particles under uniform translational motion.

ISSN:0003-6951    

DOI:10.1063/1.1654464

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

The design and performance of a remote Raman spectrometer are described. The unit has been tested at ranges from several hundred yards to a half‐mile in full daylight under both clear atmosphere and fog conditions. GoodS/Nratios were obtained for the detection of atmospheric H2O and CO2as well as SO2(300 ppm m) and hydrocarbon vapors (17 ppm m) in controlled sources, with a range resolution of 10 m. This is more than two orders of magnitude better than the best published results to date.

ISSN:0003-6951    

DOI:10.1063/1.1654465

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

The characteristics of backward‐traveling‐wave (BTW) parametric amplification and oscillation are analyzed. Effects of variations in pump excitation and interaction length on the stability of amplification, oscillation threshold, and over‐all gain, etc., are discussed in detail. In this type of interaction, a BTW signal is always amplified more effectively than an FTW (forward‐traveling‐wave) signal. The significance of BTW interactions for large pump excitation or long interaction length is also indicated.

ISSN:0003-6951    

DOI:10.1063/1.1654466

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

This letter reports the demonstration of direct optical overtone excitation of the second vibrational level of hydrogen fluoride. A unique variation of the laser‐excited‐fluorescence technique was employed in the experiment to achieve a significant nonequilibrium population of HF(v=2) within a room‐temperature mixture of HF and argon. The HF(v=2) level was excited by a pulse from a temperature‐tuned Nd:YAlO3laser, and the resultant fluorescence was monitored. The &Dgr;v=1 fluorescence from the mixture revealed the presence of a double exponential decay. The preliminary data allow the interpretation of the two exponentials as representing thev=2→v=1 andv=1→v=0 collisional deactivations. This in turn has led to an approximate value for the ratio of the time constants of the processes of &tgr;1/&tgr;2=2.2±0.4.

ISSN:0003-6951    

DOI:10.1063/1.1654467

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

We report the first demonstration of channel optical waveguide directional couplers. The closely spaced channel waveguides were fabricated in GaAs by proton implantation. Optical coupling was observed at 1.15 &mgr; with complete light transfer out of the initial channel into adjacent channels in lengths of typically 2 mm.

ISSN:0003-6951    

DOI:10.1063/1.1654468

出版商:AIP    

年代:1973

数据来源: AIP

摘要:

By using laser pulses, the kinetics of crystallization of Te‐rich films were studied as a function of light intensity and pulse duration. The initial devitrification was found to be temperature activated (&Dgr;E≃1–1.6 eV), and no evidence for photocrystallization was found. Amorphizing energies for 100‐nsec pulses ranged from 0.13 to 0.55 nJ/&mgr;2, depending on the degree of crystallization. Part of this increase is due to heat‐of‐fusion effects, but most of it is due to increased thermal conductivity with increased crystallization.

ISSN:0003-6951    

DOI:10.1063/1.1654469

出版商:AIP    

年代:1973

数据来源: AIP