摘要:

Short‐wavelength stimulated emission from a GaInP/AlGaInP double‐heterostructure (DH) grown on GaAs0.6P0.4substrates, where lattice‐matched Ga0.7In0.3P is the active layer with &Ggr; band‐gap energy beyond 2.1 eV is investigated. Laser oscillation is attained at a wavelength below 590 nm. This shows that the DH attains sufficient carrier confinement for lasing even though the minimum &Ggr; band‐gap energy is close to that in theXband. By applying high‐reflectivity coating on both facets of the cavity to decrease the optical mirror loss, we achieve lasing operation by the DH devices under pulsed current injection up to 200 K. The device exhibits threshold currents of 115 mA at 77 K and 380 mA at 200 K, and an output power level up to 0.3 mW. The oscillation wavelength is 577 nm at 77 K and 588 nm at 200 K when the current is injected at 1.2 times the threshold. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114187

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We have observed nonlinear absorption in spin‐coated poly(4,6‐decadiyne‐1, 10‐diolbis {[(n‐butoxycarbonyl)methyl]urethane}) [poly(3BCMU)] polydiacetylene channel waveguides at different wavelengths in the near‐infrared. Intensity dependent absorption coefficients, &agr;2and &agr;3, have been determined by measurements of the intensity dependent transmission. The implications of nonlinear absorption for all‐optical device applications in this material are discussed. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114188

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Numerical simulations of quantum tunneling with time‐dependent barriers show that there is a resonance, with a marked increase in the transmission coefficient. For a raised cosine potential, and for low energies with square barriers, the resonance occurs when a modulation quantum can take a tunneling particle to the top of the barrier. For energies near the top of a square barrier the resonance may be understood by hypothesizing that a tunneling particle may travel from end to end of the barrier until it is ultimately either transmitted or reflected. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114189

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Recently significant crosstalk has been observed in a multibeam experiment in which gratings were previously thought to be independent. In this letter, it is shown that the crosstalk is due to a coherent nonlinear combination of the primary gratings, which causes additional peaks to occur in the diffraction pattern and changes the diffraction efficiency of the primary gratings explaining the apparent crosstalk. It is shown that the effect can be derived from the band transport model when all the terms in the expression for the generation of charge carriers are retained. Results are presented for a configuration consisting of a reference beam and two object beams and show experimental results that confirm the model. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114190

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Strain and quantum size effects on the optical matrix elements for both TE and TM polarizations of strained quantum wells are studied theoretically including the spin‐orbit coupling. A set of universal curves for the polarization dependent optical matrix elements as a function of strain is shown. These curves will be very helpful for a quick estimate of the optical matrix elements including the effects of the spin–orbit splitoff band for modeling the optical gain and absorption using strained quantum wells. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114191

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

This letter analyzes the quality of reproduction of holograms recorded in thermoplastic media as a function of the variations in coating thickness of the different layers. The fidelity of reproduction is investigated by means of a phase sampling interferometric technique. It is found that the distortion depends on the processing parameters. A criterion for the optimization of the coating thickness of the layers is given. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114192

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Near‐infrared atomic Xe laser lines have been generated from an Ar:He:Xe laser gas mixture excited by a radio frequency (rf) discharge in a slab geometry. A maximum continuous wave (cw) output power of 1.5 W (270 W/l) was obtained at an rf frequency of 125 MHz from a gas mixture containing Ar:He:Xe (50:49:1) at a total gas pressure of 90 Torr. ©1995 American Institute of Physics. 

ISSN:0003-6951    

DOI:10.1063/1.113425

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Single‐beamZ‐scan experiments have been used to measure the two‐photon absorption coefficient &bgr; and bound electronic nonlinear refractive index &ggr; of composites of InP nanocrystals grown in 40 and 150 A˚ Vycor porous glass. These materials were also studied with two‐beam time‐resolvedZscans to confirm that the nonlinearities are instantaneous with respect to the ∼100 ps pulses used. The magnitudes of the nonlinearities in the 150 A˚ sample are found to be similar to those of bulk InP when scaled by the volume fraction of deposited material. For the 40 A˚ sample the ratio &ggr;/&bgr; is enhanced by a factor of fourteen compared to bulk InP. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113426

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

A microplasma is produced on the surface of a glass sample by a 120 fs laser excitation pulse. The optical second harmonic from the plasma is measured using a weak delayed probe pulse. It is shown that the rise and decay of electron plasma oscillations can be mapped out by measuring properly selected second harmonic components as a function of delay time. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113427

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The reactive partially ionized beam deposition technique was used to deposit amorphous BaxTi2−xOythin films with the Ba/Ti ratios from 1 for a stoichiometric BaTiO3film to 0.2 for a Ti enriched film. A postdeposition annealing between 500 and 600 °C converted stoichiometric amorphous BaTiO3into polycrystalline structure. This crystallization resulted in densification with a 9% decrease in film thickness. Off‐stoichiometric thin films remained amorphous up to 700 °C. Annealed off‐stoichiometric BaxTi2−xOyfilms, however, had lower leakage current and loss tangent than polycrystalline films due to their amorphous nature making them more suitable for electronic applications. At temperatures of 800 °C or higher, significant reaction occurred between the films and Si substrate as detected by Rutherford backscattered spectroscopy. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113428

出版商:AIP    

年代:1995

数据来源: AIP