摘要:

A broad‐band optical reflector based on the localization of light for one‐dimensional disordered systems is proposed and demonstrated both theoretically and experimentally. The binary disordered multilayer reflector consists of alternating random layers of two coating materials. Its high reflection range is much wider than that of standard &lgr;/4 stacks and can be obtained by a conventional coating method and ordinary materials. This kind of reflector will have significant applications in laser technology and optical equipment. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114597

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We recently reported a new lasing dye, trans‐4‐[p‐(N‐ethyl‐N‐hydroxylethylamino)styryl]‐N‐methylpyridinium tetraphenylborate (ASPT), which has also been shown to possess a strong two‐photon absorption (TPA) and subsequent frequency upconversion fluorescence behavior when excited with near infrared laser radiation. Based on the TPA mechanism, a highly efficient optical limiting performance has been demonstrated in a 2 cm long ASPT‐doped epoxy rod pumped with 1.06 &mgr;mQ‐switched laser pulses at 50–250 MW/cm2intensity levels. The measured nonlinear absorption coefficient reached 6 cm/GW for the tested sample of dopant concentrationd0=4×10−3M/L. The molecular TPA cross section of ASPT in the epoxy matrix is estimated as &sgr;2=2.5×10−18cm4/GW or &sgr;2′=4.7×10−46cm4/photon/s, respectively. Two‐photon pumped cavity lasing is also observed in an ASPT‐doped polymer rod. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114598

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Oriented sexiphenyl (6P) film was prepared through epitaxial growth on rubbed substrates by vacuum deposition. Polarized absorption spectra demonstrated that the long axis of 6P molecule was highly oriented along the rubbing direction. Using the epitaxial growth film of 6P, we fabricated electroluminescent (EL) devices consisting of indium‐tin‐oxide anode, emissive layer of 6P, electron‐transporting layer of an oxadiazole derivative, and MgAg alloy cathode. Owing to the orientation of 6P molecules, EL polarized in the rubbing direction was observed in the devices. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114599

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

A blue laser at 465 nm has been demonstrated by intracavity frequency doubling of the 930 nm transition in neodymium‐doped crystal of yttrium orthoaluminate (Nd:YAlO3). The compact plano–plano laser cavity comprising a 1.2‐mm‐thick Nd:YAlO3crystal and a 1.3 mm potassium niobate (KNbO3) crystal generated more than 15 mW of blue power when pumped by a Ti:sapphire laser. The blue output is linearly polarized with a TEM00spatial profile. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114600

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

A Nd3+:SrLaGa3O7laser with a pentacarbocyanine dye cell produced regular 25–30 ps pulses over the period of the flash lamp. Output energy as a function of mirror reflectivity and lamp energy was also determined. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114601

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We present cross‐correlation measurement of ultrafast switching in a symmetric Mach–Zehnder all‐optical switch. A full width at half‐maximum of 2 ps has been achieved in the cross‐correlation trace, corresponding to the estimated switching time of 1.5 ps. Both the switch‐on and switch‐off time of the measured traces are limited only by the control pulse duration of 1.1 ps. These results indicate that the effects of group velocity dispersion and intraband carrier relaxation are negligible within the present time scale. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114602

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Mach–Zehnder (MZ) waveguide interferometers integrated on SOI (silicon on insulator) for 1.3 &mgr;m operation are studied on the basis of the large cross‐section single‐mode rib waveguide condition and the free‐carrier plasma dispersion effect in Si wafer direct bonding SOI by back‐polishing. And the MZ interferometers are fabricated by using KOH anisotropic etching. Their insertion losses and modulation depths are measured to be 4.81 dB and 98%, respectively, at the wavelength of 1.3 &mgr;m when a forward bias voltage applied to ap+njunction is 0.95 V and the active zone length of the MZ interferometers is 816.0 &mgr;m. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114603

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

X‐ray diffraction, infrared, and Raman spectra of Nd‐doped LiTaO3(LT:Nd) were examined. X‐ray diffraction patterns of thexandyfaces display the appearance of new diffraction peaks and the existence of microtwin crystals, indicating the microstructural deviation from a trigonal system of pure LT crystal. Infrared transmission spectrum shows more than seven strong vibrational bands in the high frequency region 1500–6000 cm−1. Their intensities and frequencies hardly change after annealing the sample at high temperature. We attribute these bands to the existence of defects and some metal and organic complexes in the sample. Similar results were obtained from the Raman spectra. In addition, the transmitted polarized light photomicrograph of theZface of LT:Nd displays the occurrence of a helix dislocation. All experimental results indicate that the microstructural imperfection of LT:Nd can lead to some new optical effects. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114604

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Near‐infrared to visible upconversion characteristics of Er3+in CdX2‐based halide glasses (X=Cl, Br, or I) has been investigated. When4I9/2state is pumped by 800 nm radiation from an AlGaAs laser diode, the upconverted green emissions (520–560 nm) of2H11/2+4S3/2→I15/2transition are clearly observed in all the glasses. The linewidth of green emission in these glasses becomes narrow in the order of chloride, bromide, and iodide. The CdCl2and CdBr2system glasses give blue upconversion luminescence (around 410 nm) due to the2H9/2→I15/2transition, but this emission is not observed in the CdI2system glass because of the absorption edge at around 450 nm. The fluorescence spectra of CdX2system glasses suggest that the multiphonon relaxation rate depends on choice of theXspecies. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114605

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We experimentally demonstrate signal gain for picosecond signals due to an orthogonally polarized pump beam in an AlGaAs channel waveguide at a wavelength of 1.55 &mgr;m, below half the band gap. We show as much as 40% signal gain, or depletion, depending on the polarization states of the pump and the probe. The results are in good agreement with theory. ©1995 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.114606

出版商:AIP    

年代:1995

数据来源: AIP