摘要:

The polarization of vertical‐cavity top‐surface‐emitting lasers (VCSELs) is stabilized by inscribing a fine metal‐interlaced grating into the topmost &lgr;/4 layer of the distributed Bragg reflector (DBR). In this scheme, thin Al/AuZn films are deposited on the sidewalls of the grating defined by the ion milling technique. These metal films enhance polarization anisotropy of the top DBR. Grating periods of 0.9, 1.2, and 1.5 &mgr;m are tested and VCSELs with the 1.2‐ or 1.5‐&mgr;m grating show good polarization selectivity over the entire range of operating current. The direction of the dominant polarization is orthogonal to the grating line, and the polarization extinction ratio exceeds 40:1 on the average. This polarization discrimination scheme works well for all sizes of VCSELs tested. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113469

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Laser processing of insulators and semiconductors is usually realized using photon energies exceeding the band‐gap energy. This makes laser processing of insulators difficult since high photon energies typically require either a pulsed laser or a frequency‐doubled continuous‐wave laser. A new method is reported which enables us to do laser processing of lithium niobate using sub‐band‐gap photons. Using high scan speeds, moderate power densities, and sub‐band‐gap photon energies results in volume removal rates in excess of 106&mgr;m3/s. This enables fast micromachining of small piezoelectric structures, or simple etching of grooves for precision positioning of optical fibers. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113470

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

A novel method is demonstrated for the correction of cavity thickness deviations imposed by technological limitations in the growth process of a resonant cavity spatial light modulator. This method is based on cavity phase compensation through the use of an externally‐deposited dielectric Bragg mirror and provides an effective means of optimizing the device characteristics. In particular, such mirrors can significantly relax otherwise stringent epitaxial growth requirements in the fabrication of hybrid silicon/compound‐semiconductor spatial light modulators incorporating Fabry–Perot cavities. We further demonstrate deposition of a conductive, index‐tunable indium tin oxide (ITO) antireflection coating that is designed to maximize the contrast ratio and throughput of the inverted‐cavity modulator configuration. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113471

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

A series of new intramolecular charge transfer compounds with absorption bands in shorter wavelengths have been synthesized. Bright visible light emits from the crystals of these new compounds under infrared pulsed laser pumping. The spectral and pump density dependent properties demonstrate that some of the emissions are up‐conversion fluorescence due to two photon absorption. The fluorescent yields of one‐ and two‐photon absorption are in the same order at high pump density. This work demonstrates that these new intramolecular charge transfer crystals are good candidates for nonlinear optical materials. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113472

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Optically aided reading and writing of gold and tungsten mounds on proton‐implanted, multiple quantum well InGaAs/GaAs wafers has been demonstrated using an atomic force microscope (AFM). The system is relatively simple, requiring only a diode laser as the light source, providing a novel, compact, optoelectronic memory system. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113473

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Characteristics of spontaneous and stimulated emission by Eu(BFA)4−chelate in a planar microcavity of 2.5&lgr; length are studied experimentally. The spontaneous emission enhancement factor is close to unity. The observed spectral width and the angular divergence of spontaneous emission are consistent with theory. A distinct threshold for the transition from spontaneous to stimulated emission was observed with an associated decrease in the decay time of the emission. The spectral width decreased with increasing pumping power. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113474

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Beryllium (Be) diffusion into the active layers of single quantum well separate confinement heterostructure lasers grown by molecular beam epitaxy is investigated using photoluminescence absorption spectroscopy, secondary ion mass spectroscopy, capacitance–voltage profiling, and laser threshold current measurements. A significant amount of Be diffusion occurs under normal growth conditions. Large concentrations of Be in the quantum well are correlated to the lack of an exciton feature in the absorption spectrum. The amount of Be in the active region is reduced through a combination of lower Be concentration and lower growth temperature in the upper cladding region of the laser. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113475

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

An integrated optical isolator based on nonreciprocal conversion from a fundamental TM mode to a higher‐order TE mode is proposed and experimentally demonstrated. The isolator is realized using a single‐mode rib channel waveguide in Ce‐substituted yttrium iron garnet which has a very large Faraday rotation. 24 dB isolation is obtained at a wavelength of 1550 nm. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113476

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We report on the demonstration of both mechanical and optical multistability in a 110 &mgr;m diameter and 2.5 cm long Fabry‐Perot cavity defined in a dye‐doped polymer optical fiber waveguide. Such a device is a basic building block of optical and mechanical logic. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113477

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The spatial distribution of Mg solute in polycrystalline, single‐phase Al2O3has been obtained, using a secondary ion imaging technique. Segregation of Mg to the Al2O3grain boundaries is clearly observed—strong evidence that the principal role of MgO is to reduce the grain boundary mobility via a solute‐drag mechanism. In addition, Mg (dopant) and Ca (impurity) are shown to cosegregate, shedding further light on magnesium’s ability to stabilize microstructural evolution in Al2O3. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113478

出版商:AIP    

年代:1995

数据来源: AIP