摘要:

Highly crystallized polycrystalline film of single‐phase CaWO4has been prepared on a tungsten substrate at room temperature in an alkaline solution containing calcium ions by an electrochemical method with the current density of 1 mA/cm2. This film showed blue emission (456 nm wavelength) with excitation light (254 nm wavelength) at room temperature. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113563

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We demonstrate a novel long‐wavelength vertical‐cavity laser structure employing two AlAs/GaAs mirrors and a strain‐compensated InGaAsP quantum‐well active region. The lasers have been fabricated bywaferfusionand have the lowest room‐temperature pulsed threshold current density of 3 kA/ cm2at 1.52 &mgr;m. Eight laser sizes ranging from 9 to 60 &mgr;m were fabricated with threshold currents as low as 12 mA. Single transverse mode operation was observed on the 9 &mgr;m device, while other devices lased multimode. The maximum pulsed output power was 7 mW. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113564

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

A strained InGaP/GaAs/InGaAs multiquantum well laser has been monolithically integrated with GaAs metal–semiconductor field effect transistors (MESFETs) in a differential pair configuration to form a transmitter circuit. The structure utilized a single epitaxial growth step in which the laser was grown on top of the MESFET. The circuits operated with bandwidths as high as 4 GHz. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113565

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Channel waveguides of Rb+exchanged single‐crystal KTiOPO4were studied by micro‐Raman spectroscopy. Rb+exchange causes a disruption of the long‐range translational (crystal) symmetry of the lattice and a tilting of the TiO6octahedra. The ability to nondestructively map the chemical and physical structure related to the optical properties of channel waveguides is demonstrated. ©1995 American Institute of Physics. 

ISSN:0003-6951    

DOI:10.1063/1.113566

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Modification of the trap density of the photorefractive polymer compositepoly(N-vinyl carbazole)(PVK),2,4,7-trinitro-9-fluorenone(TNF) andN,N-diethyl-para-nitroaniline(EPNA) was achieved with the addition of4-(diethylamino)benzaldehyde diphenylhydrazone(DEH). Measurements of the response time, the phase shift and the amplitude of the photorefractive grating are presented. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114230

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Reduced‐finesse asymmetric Fabry–Pe´rot modulators are presented utilizing partial antireflection coatings (PAR‐ASFP). Nonuniformity in semiconductor layer thicknesses may be corrected for by adjusting the thickness of the partial antireflection layer. Reduced thickness of the semiconductor layers is corrected for byreducingthe thickness of the PAR layer, leading to natural extensions to manufacturing. By correcting the PAR, we obtain greater than 6.7:1 contrast over an entire 2 in. wafer at a single wavelength and drive voltage of 9 V. ©1995 American Institute of Physics. 

ISSN:0003-6951    

DOI:10.1063/1.113567

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Large improvements are reported in the sensitivity of optically addressed multiple quantum well spatial light modulators. In prior work with these materials the quantum well region has been made semi‐insulating. It is shown that this is unnecessary and in fact detrimental to performance. By placing layers containing high trap concentrations at the ends of the structure and leaving the active quantum well layers intrinsic the speed of the device at a given illumination is improved by more than four times, diffraction efficiency is enhanced and spatial resolution is almost the same. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113568

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

In this letter, a new type of self‐pumped phase conjugation (SPPC) is demonstrated and a phase conjugate reflectivity as high as 83.8% is measured in an unusually cut Fe‐doped KTa1−xNbxO3(KTN:Fe) crystal with a He‐Ne laser. Some novel characteristics of this type of device are found, which may reduce the need for special crystal qualities to obtain SPPC. Finally, a possible mechanism is postulated to reasonably explain this type of SPPC. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113569

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Novel aromatic and aliphatic polyimides exhibiting sizable second‐order nonlinear optical properties and long term thermal and temporal stability were synthesized. Detailed physical characterization revealed that the polymers are stable up to 300 °C with high glass transition temperatures (≳200 °C). Exceptional thermal stabilities at elevated temperatures were observed even at 150 °C. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113570

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

In‐fiber chirped Bragg gratings are used as stretchers and compressors for distortionless amplification of femtosecond pulses in chirped pulse amplification system. It is shown that using opposite directions of pulse propagation the effects of higher order dispersion and grating irregularities can be eliminated and the original pulse shape and duration can be recovered. Using these gratings a compact all‐fiber system consisting of a mode‐locked fiber oscillator and an erbium‐doped fiber amplifier was built. 330 fs bandwidth‐limited pulses from a fiber oscillator were stretched to 30 ps, amplified and recompressed back to 408 fs. The maximum energy of the pulses after the amplifier was 6 nJ and was at the threshold of nonlinear effects for a 30 ps stretched pulse. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.113571

出版商:AIP    

年代:1995

数据来源: AIP