摘要:

We have developed a new microfabrication technique for the construction of three-dimensional photonic crystals. In particular, we used multiple tilted x-ray lithography exposures in order to construct structures with photonic band gaps in the infrared region. First polymethylmethacrylate (PMMA) resist layers with a thickness of 500&mgr;mwere irradiated, then the holes in the resist structure were filled with preceramic polymer and subsequent pyrolysis converts the preceramic polymer into a SiCN ceramic. Theoretical results with fitted values of the dielectric constant are in good agreement with the transmission measurements. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120431

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Etched mirrors for semiconductor lasers are necessary for optoelectronic integrated circuit applications. This letter reports on the use of an inductively coupled plasma (ICP) reactor to create etched mirrors on GaAs/AlGaAs ridge lasers. Etch chemistries consisting of boron trichloride and chlorine were used to achieve both smooth and vertical mirror surfaces. Optical measurements indicate that devices fabricated with ICP etched mirrors are comparable to devices formed by cleaved mirrors. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119931

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Linearly polarized soft x-rays are converted to elliptical polarization at the FeL3line (707 eV) using magnetic circular dichroism (MCD) on transmission through thin Fe films. A linear polarizer measured the transmitted polarization at different incidence angles to vary as expected from a model for in-plane magnetization, and also to exhibit a weak MCD effect at normal incidence interpreted to originate from perpendicular interface anisotropy. An MCD signal from a downstream Fe film was produced by switching the helicity of x-rays transmitted through an upstream circular polarizer. Practical considerations for optimizing the production of circular polarization are discussed, and synchrotron radiation applications using these circular polarizing filters are suggested.

ISSN:0003-6951    

DOI:10.1063/1.119932

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Data are presented on vertical-cavity surface-emitting lasers that use tunneling for injection of electrons into a quantum well active region. The tunneling injection scheme increases the electronic confinement and improves the lasing performance for small active areas. A lasing threshold of 36 &mgr;A with a slope efficiency of 23&percent; is achieved for a 2.5 &mgr;m device, and a 52&percent; slope efficiency is achieved for a 4 &mgr;m device with a 92 &mgr;A threshold. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119933

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We demonstrate a free-space magneto-optic sampling system to measure the transient magnetic component of a freely propagating terahertz beam. Preliminary results using two magneto-optic sensors are presented. A detection sensitivity of10−7 Tof the picosecond magnetic field in a standard pump/probe configuration is obtained. In the current orthogonal geometry, a 13 ps risetime of the free-space magneto-optic signal is measured. A temporal resolution limited only by the material spin relaxation time in a velocity-matched geometry is anticipated. ©1997 American Institute of Physics. 

ISSN:0003-6951    

DOI:10.1063/1.119934

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Reconfigurable optical properties were studied in InGaN/GaN multiple quantum well (MQW) structures. It was observed that a short time exposure to a high intensity ultraviolet light results in long term, but reversible changes of the optical properties of InGaN/GaN MQW samples. The photoinduced changes can be observed using an optical microscope under low intensity ultraviolet light and are visible as a high contrast pattern. The retention time at room temperature for 12 and 20 MQW samples was longer than five days and four weeks, respectively. The effect was studied at room and cryogenic temperatures. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119935

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Laser cooling of a solid can occur when it emits photons of higher mean energy than those it absorbs. Photothermal deflection spectra of a fluorozirconate glass (ZBLANP) doped with 1 wt&percent;Yb3+show cooling in an internal volume of the sample at temperatures between 100 and 300 K. A cooling efficiency of ∼1&percent; relative to the absorbed laser power at 1015 nm is maintained at all temperatures. The results show promise for solid-state cooling of bulk materials at temperatures below 150 K.©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120441

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We measured temporal evolution of the coherent emission from a semiconductor microcavity by a very sensitive ac balanced homodyne detection system. We observed collapse and revival of the exciton–polariton oscillation due to a three-mode beating. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119936

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The film shrinkage effect of photopolymeric phase media failed to provide the desired volume holograms for point-to-point optical interconnects. In this letter, we report a compensation method to physically correct the shrinkage effect that resulted from the holographic recording and the postbaking. Dupont photopolymer HRF-600X001 is studied. The correction of the Bragg diffraction angle shift of1°21′,which is induced by a 5.25&percent; film shrinkage, is successfully demonstrated with the surface-normal configuration. A shrinkage-corrected volume hologram with 80&percent; diffraction efficiency is experimentally confirmed. The methodology reported herein is applicable to other phase media when the associated film shrinkage data are experimentally determined. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119937

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

A spatially resolved optical emission spectroscopy sensor has been developed, and the resulting reconstructed radial emission profiles from an ArI and ArII line compare well with Ar sputter etch uniformity profiles. The new sensor collects light from a wedge shaped field of view, and is rotated around a single collection point in order to observe the entire plasma through a relatively small viewpoint. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119938

出版商:AIP    

年代:1997

数据来源: AIP