摘要:

Narrow‐band optical feedback is an effective method of reducing the linewidth and stabilizing the frequency of diode lasers. We have constructed an optically stabilized AlxGa1−xAs/GaAs laser using a rubidium vapor cell immersed in a dc magnetic field as an optical feedback element. The diode laser’s frequency locks to sub‐Doppler features of the rubidium spectrum and exhibits a reduction in linewidth from 30 MHz to 35 kHz.

ISSN:0003-6951    

DOI:10.1063/1.105214

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We have studied the spontaneous emission properties of Langmuir–Blodgett films containing dye molecules confined in Fabry–Perot microcavity structures having wavelength thickness. The presence of the cavity causes great modifications in the emission spectrum and emission intensity in the direction of the cavity axis. A clear change in spontaneous emission lifetime occurs, which is also attributed to the microcavity effect.

ISSN:0003-6951    

DOI:10.1063/1.104388

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

A nonlinear periodic structure can convert an input continuous wave beam into a train of pulses. This modulational instability implies that the nonlinear spatial resonance (‘‘gap solitons’’) of distributed feedback structures are generally unstable. Stability is assured only for low coupling strengths or large detunings from the Bragg condition.

ISSN:0003-6951    

DOI:10.1063/1.104404

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

By multiphoton ionization of cadmium vapor with a high peak power femtosecond KrF‐excimer laser system, a cold and dense plasma is generated. In a fast recombination process an inversion in the atom results, leading to strong short‐pulse laser oscillation at &lgr;=508 nm. Also superfluorescence phenomena have been observed.

ISSN:0003-6951    

DOI:10.1063/1.104405

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

A serious problem of high‐power GaAs/AlGaAs laser diodes is the strong mirror heating, which is caused by the carrier density and the correlated nonradiative surface recombination at the cleaved mirrors. Therefore the top electrode was segmented in three parts and the influence of a separate controllable potential in the mirror region on the temperature has been studied. The local temperature was measured using spatially resolved Raman scattering. A substantial reduction of the mirror temperature is possible by applying a suitable potential to the mirror contacts. This may lead to an improvement in reliability in the case where the high mirror temperature is responsible for the degradation of the laser.

ISSN:0003-6951    

DOI:10.1063/1.104406

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

High‐efficiency InGaAlP surface emission light emitting diodes (LEDs) have been successfully fabricated. Newly designed double‐heterostructure LEDs with a GaAlAs current spreading layer were employed to expand the light emission area, which is necessary to take out the light efficiently. The external quantum efficiency was 1.5% at 620 nm orange light for an In0.5(Ga0.8Al0.2)0.5P active layer LED. This LED is five times more efficient at 620 nm than that of the GaAlAs and GaAsP LEDs. 563 nm green electroluminescence, which is the shortest wavelength ever reported for InGaAlP LEDs, was also achieved with an In0.5(Ga0.5Al0.5)0.5P active layer.

ISSN:0003-6951    

DOI:10.1063/1.104407

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

The measured reflectances of initial, colored and bleached polycrystalline WO3films prepared by spray pyrolysis are presented and compared with the calculated reflectances using a theoretical model −Drude theory.

ISSN:0003-6951    

DOI:10.1063/1.104408

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We report the electric field induced refractive index variation spectrum in a GaInAs/InP multilayered (three layers) quantum wire structure (&lgr;g∼1.48 &mgr;m) in the range 1.484–1.65 &mgr;m with the maximum positive index variation of 4% at around 1.52 &mgr;m at an applied reverse bias voltage of 3 V. We have also observed the anisotropic property of the index variation with respect to the quantum wire direction to the input light. These multilayered quantum wire structures were fabricated by low‐pressure electron cyclotron resonance reactive ion beam etching and low‐pressure organometallic vapor phase epitaxy methods.

ISSN:0003-6951    

DOI:10.1063/1.104409

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Nonlinear optical effects have been measured in a novel heteron‐i‐p‐istructure with strained InAs/GaAs superlattices as the quantum wells. For intensities below 6 W/cm2, changes in transmission are observed due to the screening of built‐in fields in conjunction with the quantum‐confined Stark effect. For intensities greater than 30 W/cm2, a further increase in transmission is observed due to state filling and exciton screening in the wells. It is demonstrated that an‐i‐p‐istructure, because of its lengthened carrier lifetime, can be used to reduce the intensity necessary for exciton saturation and state filling in quantum wells when the wells are placed in theiregions. Total changes in transmission greater than 25% have been seen, with no sign that the nonlinearity is saturating at 1 kW/cm2(the highest excitation used here).

ISSN:0003-6951    

DOI:10.1063/1.104410

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

A technique to extrude pure sodium wires has been developed and this has allowed the implosion of sodium wire arrays on the 4 MA, 6 TW Double Eagle generator. A maximumK‐shell x‐ray yield of 35 kJ was achieved. Of particular interest, as regards the sodium‐neon x‐ray laser scheme, is the measured 150 GW, 8 kJ in the NaX 1s2–1s2p 1Pline at 11.0027 A˚.

ISSN:0003-6951    

DOI:10.1063/1.104411

出版商:AIP    

年代:1991

数据来源: AIP