摘要:

In this letter we report on the pulsed laser epitaxial deposition of thin films of Sr0.75Ba0.25Nb2O6on MgO substrates with measured diagonal Pockel’s coefficientr33=844 pm/V in these films. This is the largest linear electro‐optic coefficient reported to date in a thin film material. In order to measure this coefficient, we developed a modulated diffraction technique. This method is widely applicable to cases where the substrate is insulating and the optical axis is normal to the substrate. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.116919

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

We report on a novel electro‐optic sampling system for real‐time terahertz (THz) imaging applications. By illuminating a 6×8 mm2ZnTe crystal with a 300 &mgr;W optical sampling beam and detecting the beam with a digital CCD camera, we achieved time‐resolved images of pulsed far‐infrared radiation emitted from an unbiased GaAs wafer. At the focal point of the peak far‐infrared field, the THz beam diameter is approximately 0.75 mm (full width at half‐maximum). The temporal and spatial resolutions of this imaging system are mainly limited by the laser pulse duration and the diffraction limit of the THz beam, respectively. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.116920

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

We report a singly resonant optical parametric oscillator in periodically poled lithium niobate, synchronously pumped by the second harmonic of an amplified 10 &mgr;s pulse train from a continuous wave mode‐locked Nd:YLF laser. Pulses of ∼2 ps duration have been generated over the tuning range from 883 to 1285 nm with a typical threshold of 200 mW average power within the 10 &mgr;s envelope. TheM2beam quality factor for the generated signal was ∼1.1, indicating absence of any significant photorefractive damage. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118166

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

KTiOPO4(KTP) crystals were grown from K6 (K6P4O13) flux in various ambients. A colorless KTP crystal was obtained in an oxygen deficient ambient. It has been found that the absorption coefficient in the region from 400 to 550 nm and Pt inclusion concentration increased with the oxygen concentration in the growth ambient. The strong correlation between the absorption coefficient and Pt impurity concentration suggests that the absorption of KTP crystal is attributed to incorporated Pt ions in the crystal. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.116921

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

The chemical and physical properties of photobleached nonlinear optical (NLO)‐polymethacrylates were studied in order to investigate photobleaching mechanisms. We have shown by three key measurement techniques (infrared‐spectroscopy, mass spectrometry, and gel permeation chromatography) that the predominant bleaching process is an irreversible decomposition of the NLO moieties accompanied by a broadening of the polymer molecular weight distribution. The quantum yield of the chromophore degradation determined by the evaluation of the bleaching kinetics fit is in agreement with typical data from comparable chromophores. It was found that bleaching causes an increase in surface roughness of NLO‐polymer films, causing an increase in waveguide loss. Smoothing of the film surface by an annealing step leads to a lowering of bleaching induced waveguide loss. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.116922

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

We consider theoretically a novel lasing scheme in semiconductor quantum boxes. Ultralow threshold pumping power can be obtained due to the development of images charges in surrounding layers. The impact on the intersubband lasing is stressed. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.116923

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

We report a new technique to apply strain to a vertical‐cavity surface‐emitting semiconductor laser. This has allowed us to study the relation between strain and birefringence. We have found that the corresponding tensor is anisotropic, with a measured anisotropy 2p44/(p11−p12)=4.7±0.6. This anisotropy explains the natural preference of the polarization for the [110]/[11¯0] axes. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.116924

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

Fine droplets of nematic liquid crystal (LC) with a diameter less than 100 nm were obtained in ultraviolet curing polymers. The transparency of the material was kept high in the infrared regions because there was little scattering in comparison to materials containing much larger droplets. The fine droplets were found to respond to an electric field, causing a change in birefringence. This change was about 0.0004 at the applied voltage of 5.5 V/&mgr;m. The special features of low transmission loss and easy film formation will enable one to apply LCs to optical devices of the wave guide type. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.116925

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

A photorefractive polymer system based on a substituted polysiloxane backbone is described. In addition to high holographic diffraction efficiency and reasonable writing speed, the material reported exhibits excellent optical clarity and low optical scattering characteristics. These latter optical properties are necessary in high density holographic digital data storage applications. The utility of the polysiloxane based photorefractive polymers for storage applications is demonstrated by recording digital data at a density of 0.52 Mbit/cm2and reading it back without error. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.116926

出版商:AIP    

年代:1996

数据来源: AIP

摘要:

We demonstrate a measurement technique for determining the contribution of carrier transport effect on the maximum modulation bandwidth in quantum well lasers. This technique independently measures the ratio of the effective carrier capture to escape times, as well as the contribution from intraband damping mechanisms, in an operating laser. Every single parameter in the present model for modulation dynamics of quantum well lasers can now be determined experimentally, which enables a consistency check on its validity. ©1996 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.116927

出版商:AIP    

年代:1996

数据来源: AIP