摘要:

The wavelength‐dependent loss increase in the long wavelength region is revealed for phosphor‐doped silica fiber at a high temperature around 200 °C. The loss increases around 1.3 &mgr;m and becomes larger for longer wavelength regions. The loss increase is suppressed by reducing P2O5dopant concentration. The overtone absorption of Ge–OH at 1.41 &mgr;m as well as that of Si–OH at 1.39 &mgr;m also increases markedly. The possible origin of the loss increase is discussed.

ISSN:0003-6951    

DOI:10.1063/1.94343

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

It is demonstrated experimentally that the intrinsic modulation response of injection lasers can be modified by reducing mirror reflectivities, which leads to suppression of relaxation oscillation resonance and a reduction of nonlinear distortions up to multi‐GHz frequencies. A totally flat response with a 3‐dB bandwidth of 5 GHz was obtained using antireflection coated buried heterostructure lasers fabricated on a semi‐insulating substrate. Harmonic distortions were below 40 dB within the entire 3‐dB bandwidth. These results are in accord with theoretical predictions based on an analysis which include the effects of superluminescence in the laser cavity.

ISSN:0003-6951    

DOI:10.1063/1.94344

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

The possibility of phononless free‐carrier absorption in quantum well heterojunction superlattices was investigated. Order of magnitude calculation showed that the absorption coefficient was significantly enhanced over the phonon‐assisted process. Important aspects of the enhancement in the design of infrared photodetectors are discussed.

ISSN:0003-6951    

DOI:10.1063/1.94345

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

The technique of pulsed photothermal radiometry (PPTR) (i.e., detection of the transient infrared thermal radiation from a condensed matter sample heated by a short‐pulsed radiation) is useful for single‐ended remote sensing applications. We demonstrate for the first time such applications for spectroscopic detection, measurement of absolute absorption coefficients in opaque materials, and sensing of dimensions or thermal properties in inhomogeneous materials. Theory of the PPTR technique in the simple case of a semi‐infinite homogeneous material is described.

ISSN:0003-6951    

DOI:10.1063/1.94346

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

Optical absorption peaks at 760 and 500 nm in LiNbO3are assigned to oxygen vacancies containing one and two electrons, respectively. The 500‐nm band appears after annealing above approximately 500 °C in a vacuum, i.e., a reducing atmosphere, and continues to grow with increasing anneal temperature. Optical bleaching near 77 K destroys the band at 500 nm and produces both a band at 760 nm and a Nb4+electron spin resonance spectrum. The spectral dependence of the bleaching light required to convert the 500‐nm band to the 760‐nm band is determined.

ISSN:0003-6951    

DOI:10.1063/1.94347

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

We proposed and demonstrated for the first time an electronically gateable mode‐locked semiconductor laser capable of coding information on the picosecond optical pulses emitted. We further introduced an electronically controllable optical absorber which made it possible to electrically control the optical performance of the mode‐locked semiconductor laser.

ISSN:0003-6951    

DOI:10.1063/1.94348

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

A liquid crystal display based on bistable boundary layer configurations has been shown previously [Chengetal., Appl. Phys. Lett.40, 1007 (1982)] to have memory, adequate contrast, low‐voltage operation, and a bistability that is relatively insensitive to changes in material properties, cell parameters, and temperature. We report here the discovery that a short, low voltage dc pulse switches the display into one or the other of its bistable states, depending on the polarity of the pulse. Experiments suggest that a storage display of this type havingnlines of pels can be rewritten in (50+20n) milliseconds using voltages of less than 2 V. Consequently, a large area, low power, nonrefreshed display is possible.

ISSN:0003-6951    

DOI:10.1063/1.94330

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

A surface emitting AlGaAs/GaAs double heterostructure light‐emitting diode (LED) and an amplifier composed of three GaAs field‐effect transistors have been first integrated on a single GaAs substrate. Molecular beam epitaxy has been extensively used to grow a six‐layer heterostructure involving a high resistivity AlGaAs layer for electronic isolation. Input voltage to output optical power transfer characteristics are presented. It has also been shown that this integrated device successfully operates at the speed limited by the LED rise time, 7 ns in the present case.

ISSN:0003-6951    

DOI:10.1063/1.94331

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

XeCl excimer laser excited by longitudinal gas discharge is reported. The main characteristics of the laser output and the laser energy in dependence of the operating parameters were measured. The laser pulse duration was 35 ns and the maximum laser energy 317 &mgr;J with improvement by preionization.

ISSN:0003-6951    

DOI:10.1063/1.94332

出版商:AIP    

年代:1983

数据来源: AIP

摘要:

We report the piezoelectric detection and thermoelastic signals resulting from resistive heating within a diffused resistor and commercial packaged transistor. cw and pulse experiments at 5 V and 300 kHz, as well as 5‐V 10‐MHz mixing experiments, result in transducer outputs in the 25 &mgr;V–1 mV range. Theoretical values are in good agreement with experimental findings.

ISSN:0003-6951    

DOI:10.1063/1.94333

出版商:AIP    

年代:1983

数据来源: AIP