摘要:

A linear array of surface‐emitting distributed Bragg reflector AlGaAs diode lasers has been demonstrated. The intensity pattern for five emitting elements had structure with an angular divergence as low as 0.05°, indicating phase locking between the elements of the array.

ISSN:0003-6951    

DOI:10.1063/1.98246

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

In optical pulse compression experiments in the femtosecond regime, cubic phase distortion can adversely affect the compression ratio. This distortion arises from both the cubic phase of the grating pair used in such experiments and also from pulse propagation in the fiber, when taking into account the cubic order dispersion and shock terms. We numerically analyze how the cubic distortion, which leads to nonlinearly chirped pulses, can be compensated by Gires–Tournois interferometers. We discuss design considerations and show how the use of such interferometers can lead to even shorter optical pulses by utilizing more of its available bandwidth.

ISSN:0003-6951    

DOI:10.1063/1.97889

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

We report an improved time‐resolved luminescence spectroscopy system using sum frequency generation. The system has the following attributes: high time resolution (<400 fs, currently limited by the laser), ability to determine absolute zero in time delay with high precision, wide spectral range, and large dynamic range which allows measurement of luminescence under weak photoexcitation. We illustrate these with examples of time‐resolved luminescence spectra from GaAs.

ISSN:0003-6951    

DOI:10.1063/1.97890

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Multigigahertz waveforms in an InGaAs/InP metal‐insulator‐semiconductor field‐effect transistor inverter circuit have been measured noninvasively using the electro‐optic sampling technique with pulses from a gain‐switched InGaAsP laser. Propagation delays as low as 15 ps in a single inverter stage have been measured.

ISSN:0003-6951    

DOI:10.1063/1.97891

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

We attribute the single longitudinal mode operation of some Er‐doped 1.5‐&mgr;m InGaAsP lasers, observed here, to inhomogeneities in the active layer resulting from the Er. These results do not rule out the possibility of gain narrowing by the Er when Er is properly incorporated in the active layer.

ISSN:0003-6951    

DOI:10.1063/1.97892

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Numerical estimates of lateral current spreading and carrier diffusion in multiple‐stripe‐geometry AlGaAs lasers, both with and without zinc diffusion, are presented. This is the first analysis of the effect of zinc diffusion on the injected current and carrier density profiles. Results show that with a higher zinc diffusion depth, these lasers have significantly reduced current spreading, lower operating currents, and improved carrier density profiles. However, the higher zinc diffusion depths may lead to some undesirable dips in the injected current density profiles.

ISSN:0003-6951    

DOI:10.1063/1.97893

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

A modal gain analysis for diode laser diffraction‐coupled arrays which takes into account evanescent coupling in the waveguide section of an array is presented. Theoretical predictions are supported by comparisons of patterns from typical double‐heterostructure and large‐optical‐cavity lasers.

ISSN:0003-6951    

DOI:10.1063/1.98256

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

The distributions of optical emission intensity along the discharge axis in multiple‐parallel‐plate ac glow discharges were measured in the presence of a magnetic field perpendicular to the discharge electric field. In a SiH4(10%)/Ar discharge, time‐averaged spectroscopic measurements showed that profile control of not only plasmas but also SiH* was possible by varying the field strength. The emission intensity of SiH* was increased with the field strength. These results suggest that the present new configuration with cross magnetic field can make thin films on a large‐area substrate outside the multielectrodes uniform and can enhance the deposition rate.

ISSN:0003-6951    

DOI:10.1063/1.97894

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Experimental measurements in the positive column of wall‐confined high‐current hydrogen thyratron discharges show a pronounced increase in atomic hydrogen excited state populations after the end of the current pulse. The decay rate of the electron and excited state population is observed to decrease as the energy flux increases. A time‐dependent collisional‐radiative model is used to calculate electron and excited state densities. This model is in reasonable agreement with experimental measurements and explains the afterpulse behavior. The analysis shows that the coupling between electron and atom temperatures is an important mechanism in high‐power thyratron recovery. A new method using laser‐induced fluorescence to obtain time‐resolved Stark broadening data for electron density measurements is presented.

ISSN:0003-6951    

DOI:10.1063/1.97895

出版商:AIP    

年代:1987

数据来源: AIP

摘要:

Externally sustained discharges can be used as opening and closing switches in pulsed power systems. Admixtures of attachers allow rapid opening when the external sustaining source is terminated; however, they will increase losses in the closing phase. Photodetachment has been proposed as an additional control mechanism to overcome these losses. This letter presents measurements on photoionization sustained discharges in argon and nitrogen containing admixtures of oxygen under the influence of laser radiation. Strong changes of the voltage‐current characteristics have been observed. The influence of parameters such as percentage of O2, laser power, laser pulse width, and circuit impedance is presented. Additionally, it is shown that photodetachment can enhance the stability of diffuse discharges.

ISSN:0003-6951    

DOI:10.1063/1.97896

出版商:AIP    

年代:1987

数据来源: AIP