摘要:

A new type of optical switching device is developed. For a semiconductor laser amplifier with a shallow-etched bending ridge waveguide, the laser beam could propagate along the bending direction or the straight direction. Switching between the two directions is characterized. With the device fabricated on the substrate with two quantum wells of different widths, switching characteristics are found to significantly depend on the spectral separation of the two lasing modes. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119977

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Carbon nanotubes dispersed in ethanol are aligned by an electric field. Due to the orientation of these elongated particles, the dispersion exhibits anisotropic behavior. Transmission experiments show rotation of the linear polarization of an incident laser beam. Alignment and relaxation times and the influence of the magnitude of the electric field have been measured. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119976

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Ultrasonic trapping of locomotive organisms was studied by using paramecia of∼0.2 mmsize. An ultrasonic standing wave of∼3 MHzwas generated in a sample cell to trap the paramecia. When the ultrasonic oscillation was turned on, paramecia began to swim along the nodes of the standing wave. Furthermore, when two ultrasonic waves were crossed orthogonally in a thin sample cell, paramecia were trapped at the lattice points of the nodes. The trapping efficiency increased with the ultrasonic power density. The locomotive force of the paramecia was estimated from the threshold power density for trapping. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120436

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Exact calculations of the transmittance of surface corrugated optical waveguides are presented. The elastic scattering of diffuse light or other electromagnetic waves from a rough surface induces a diffusive transport along the waveguide axis. As the length of the corrugated part of the waveguide increases, a transition from the diffusive to the localized regime is observed. This involves an analogy with electron conduction in nanowires, and hence, a concept analogous to that of “resistance” can be introduced. We show an oscillatory behavior of both the elastic mean-free path and the localization length versus the wavelength. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119978

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We have studied the process of sealing an exposed AlAs to prevent further wet oxidation. A critical step in this sealing process consists of the first wet oxidation for a short time at 408 °C in a steam environment of a previously room-ambient exposed AlAs surface. During this brief wet oxidation, a dense oxide surface barrier with a thickness of 1.1 &mgr;m is formed, which further blocks diffusing oxygen species during the second wet oxidation. The effectiveness of the sealing is demonstrated through its use as a mask against wet oxidation in the fabrication of oxide-confined vertical-cavity surface-emitting lasers. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119979

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We demonstrate the fabrication of a long-wavelength laser on a (211) InP substrate, with the expectation of reducing threshold current density. We found that InGaAsP single quantum wells (SQWs) could be fabricated with good optical properties provided the SQW layers were not made too thin. A laser that had an unstrained multiple-quantum-well active layer emitting at 1.3 &mgr;m was fabricated on a(211)AInP substrate. Its threshold current density was 900A/cm2,which is comparable to the value for the same type of laser on a (100) substrate. These results suggest that long-wavelength lasers with satisfactory quality can be fabricated on a(211)Asubstrate. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119980

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We report the use of substituted main-chain poly-carbazoles as hole and electron transporting polymers for electroluminescence (EL) applications. The polymers are soluble in common organic solvents and high quality thin films are obtained by spin coating method. A single layer of hole or electron transfer devices with indium tin oxide anode and aluminum cathode shows current densities up to 40–50mA/cm2,respectively, but no visible emission from either layer. Double-layer structures combining the hole and electron transfer polymers show strong emission originated from the electron transfer layer. The peak of double-layer EL spectrum is about 30 nm redshifted to the peak of corresponding photoluminescence spectrum, which may be due to the formation of an exciplex between the two layers. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119981

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

A nonlinear optical waveguide fabrication process for use with dye doped polymer is described. The ridge-type channel waveguide containing the chromophores was fabricated by direct electron-beam irradiation. The electron beam with an energy of 25 kV and dose of 1000&mgr;C/cm2was exposed directly onto the dye doped polymer film, and then thermal development and corona-poling were performed simultaneously. We could also demonstrate the periodically poled nonlinear optical polymer waveguide on the basis of this new process. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119982

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The energy conversion efficiency and the damage threshold of aCsLiB6O10crystal have been measured for a pulse train with 80 pulses at 532 nm, each with energy up to 200 &mgr;J, 14 ps duration and 25 ns pulse to pulse spacing. Maximum energy conversion efficiency of 38&percent; has been measured when the crystal was used to convert 532 nm to 266 nm. The damage threshold of the crystal for this pulse train was measured to be >130 and <520GW/cm2.Both the high intensity of the micropulse and the fluence of the macropulse appear to affect the damage threshold. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119983

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Er3+-related electroluminescence (EL) at ∼1.54 &mgr;m from single-crystal silicon light-emitting diodes fabricated by erbium and oxygen co-implantation and subsequent annealing has been observed in the avalanche breakdown regime in the 80–300 K temperature range. The EL intensity decreased by a factor of 2 with a temperature increase from 80 to 300 K. The room-temperature yield under the reverse bias was over one order of magnitude higher than that under the forward bias. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119984

出版商:AIP    

年代:1997

数据来源: AIP