摘要:

The second‐order nonlinear optical coefficientsd33,d31, andd15of GaN:Mg epitaxial film were studied by the standard Maker fringe of an anisotropic medium. The measuredd33=−(16.5±1.3) pm/V which is 55 times of thed11of quartz. The measured ratios ofd33/d31andd31/d15showed that the crystalline film is close to an ideal wurzite structure. The refractive indices and the dispersive curves ofne,n0were also determined by TM and TE waveguide mode measurements. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.117741

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

It is demonstrated that a porous silicon (PS) optical cavity is available for the electroluminescence (EL) PS diode configuration. The PS diode is composed of a thin Au film, a light‐emitting PS layer, a multilayered PS mirror, ap‐type Si substrate, and an ohmic contact. When a sufficient bias voltage is applied to the diode, a uniform visible light emission is observed through the top contact. The EL intensity is fairly proportional to the driving current over a wide range of operation. The bandwidth of the EL spectrum is significantly reduced in comparison to that of the conventional PS diodes, owing to a resonance effect induced between the Au film and the multilayered PS mirror. These results suggest that the PS technology is a promising process for applications in monolithic integrated optoelectronics. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.117742

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

We demonstrate an integrated, two‐color organic light‐emitting device for flat‐panel display applications. The device utilizes a unique stacked pixel architecture which allows for independent tuning of color and intensity. Each of the two addressable colors is sufficiently bright for video display applications, so that the compact stacked pixel, which maximizes display resolution, may form the basis of a new type of full‐color display. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.117743

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

We investigated electrical conduction phenomena, which occurred during high electric field electrode poling of side chain &khgr;(2)polymers. Electric current and second harmonic intensity were measured simultaneously in poling experiments performed on samples with and without an additional inorganic poly–methyl–siloxane layer. Current densities appeared to be limited by a Schottky‐type potential barrier at the electrode/insulator interface. The field dependence of the current density was found to beSchottkychargeemissionfor medium field strengths (EPOL≤100 V/&mgr;m) whereas it was dominated byFowler–Nordheimtunnelingat higher poling fields. In the presence of the siloxane layer, a significant suppression of tunneling current was observed. This leads to a reduced probability of singular dielectric breakdown events and shifts the limit of avalanche breakdown to higher internal effective poling field strengths. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.117744

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

We present a combined theoretical and experimental study of the anisotropy in the optical absorption of V‐shaped quantum wires. By means of realistic band structure calculations for these structures, we show that detailed information on the heavy‐ and light‐hole states can be singled out from the anisotropy spectraindependentlyoftheelectronconfinement, thus allowing accurate valence band spectroscopy. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.117745

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

We report on the fabrication of channel waveguides in epitaxial grown BaTiO3layers on MgO. Layers were prepared by metalorganic chemical vapor deposition. Ridge waveguides with ridge heights ranging from 15 to 200 nm were fabricated in a 0.2‐&mgr;m‐thick film. Single mode waveguide throughput, scattering loss, and mode profiles are reported. Coating waveguides with spin on glass significantly increase waveguide throughput. Throughputs of up to 10.4% were measured in 15 nm ridge waveguides which were 2.85 mm long and coated with spin on glass. Waveguide throughput is found to increase significantly with an increase in wavelength from 1.06 to 1.55 &mgr;m. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.117746

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

The nonlinear molecules dispersed in the polymer with low glass transition temperature (Tg) can be easily reoriented. The plasticizer is utilized in order to lower theTgof the polymer matrix. We measured the frequency responses of second‐harmonic generation in a dye doped plasticized polymer to clarify the electric field dependence of the second‐order optical nonlinearity. We utilize poly(methyl methacrylate) doped with 2‐methyl‐4‐nitroaniline as the dye doped polymer. di(ethyl‐2 hexyl) phthalate is used as the plasticizer. The experimental results show that the rotational mobility was enhanced up to ten times by a DOP dose of 13.5 wt% in comparison with a dose of 0 wt% at 20°C. Therefore, this method is useful to increase the controllability of the optical nonlinearity by the electric field at room temperature. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.117747

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

This letter reports a measurement of the mean electron‐hole pair creation energy in crystalline silicon using photons in the 50–1500 eV spectral range. A cryogenic electrical substitution radiometer in combination with monochromatized synchrotron radiation was used to determine the spectral responsivity of silicon photodiodes in this spectral range with a relative uncertainty of less than 0.3%. The mean electron‐hole pair creation energy has been determined from these measurements and in contrast to recent theoretical and experimental results a constant value of (3.64±0.03) eV was obtained in accordance with a calculation presented here. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.117748

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

Epitaxial Nd‐doped yttrium aluminum garnet (NdxY3−xAl5O12or Nd:YAG) films have been grown on various substrates by pulsed laser deposition for the purpose of fabricating diode‐pumped waveguide lasers. The films were characterized by Rutherford backscattering, x‐ray diffraction, atomic force microscopy, and photoluminescence measurements. Nd:YAG films on (100) silicon substrate with a large lattice mismatch show oriented stoichiometric growth. On the other hand, Nd:YAG films on garnet substrates (NdundopedGd3Ga5O12,Y3Al5O12and Zr‐, Sc‐doped Gd3Ga5O12) show epitaxial growth with smooth surfaces. The optical properties of Nd‐doped YAG thin films on various substrates were comparable to those of Nd:YAG bulk laser crystal. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.117749

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

The porous silica dispersed with silver nanometer particles (about 3 nm) within its pores (cages) has been prepared by a new method. In the process of alternative exposure to the ambient air and annealing, this material assumes reversible transition between transparency and opacity. This can be explained by oxidation of the outer part of the Ag particles during exposure to the ambient air and dissociation of the oxide during annealing in air. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.117750

出版商:AIP    

年代:1996

数据来源: AIP