摘要:

A quantum well simultaneously subjected to a 1 kV/cm, 1 THz field, and a 100 fs optical pulse is shown to result in emission of a sub-ps strong upshifted ∼10 THz transient. ©1997 American Institute of Physics. 

ISSN:0003-6951    

DOI:10.1063/1.118815

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

A method of providing asymmetric feedback in the triangular ring laser structure was devised through the simple alterations of the waveguide shape. Two kinds of alterations were designed and implemented, one being the “optical diode,” the other being the tapered waveguide. Unidirectional operation was achieved for the ring lasers, with a single-beam slope efficiency of 0.23 W/A, which was the highest single-beam slope efficiency reported for semiconductor ring lasers. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118527

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The application of wavelength modulation absorption spectroscopy in the characterization of lineshape functions of molecular spectra is discussed theoretically, and experimental results for the weak spin-forbidden, magnetic dipole-driven transitions of the oxygenAband are provided. Factors affecting the accuracy of the method are discussed, and it is shown that the technique allows one to accurately probe absorption lineshape functions by using a simple, cost-effective apparatus. The advantages of using detection harmonics greater than the commonly used second are discussed, including an investigation of wing structures of absorption lines and the measurement of collision cross sections. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118528

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

A study of a high-power blue–greenXeF(C–A)laser photolytically pumped by an open discharge along a formed-ferrite surface is presented. A laser output energy of 1.3 J was extracted from a gas mixture of 4 TorrXeF2,230 TorrN2,and 680 Torr Kr, with a stable optical resonator. With a flat optical resonator, a laser output energy of 1 J was obtained. In this case, we observed an oscillating regime of the laser power, which indicates that the unsaturated gain value was close to the laser action threshold. Perspectives of optical pumping schemes are presented. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118529

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Frequency doubling of a 684 nm laser diode in a first-order periodically poledLiTaO3is presented. Controlling the side growth of the domain inverted region during high-voltage pulse application, a uniform nonlinear grating with a period of 1.7 &mgr;m and 50&percent; duty cycle was fabricated over 10 mm interaction length in a 150 &mgr;m thickLiTaO3substrate. A 342 nm wavelength of harmonic ultraviolet light was generated in a single pass through the domain-inverted structure. ©1997 American Institute of Physics. 

ISSN:0003-6951    

DOI:10.1063/1.118530

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We present the first observation by transmission electron microscopy of glass densification induced by Bragg grating inscription in two germanosilicate single-mode optical fibers. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118531

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Photoluminescence (PL), electron spin resonance (ESR), and high resolution transmission electron microscopy (HRTEM) were used to investigate the luminescence mechanism in Si nanocrystals. Si ions were implanted inSiO2films at 190 keV to a dose of3×1017/cm2.An intense photoluminescence (PL) band at 755 nm (1.65 eV) was observed when the implanted films were annealed above 800 °C in air or in nitrogen. HRTEM images showed Si nanocrystals of sizes between 1 and 6 nm from these annealed samples. ESR indicated Si dangling bonds. Upon annealing at 900 °C in air a few times, the particle sizes were reduced to less than 2 nm due to oxidation. The red PL band is attributed to emission from Si nanocrystals. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118275

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Resonant grating-waveguide structures were used for the excitation of long-range surface plasmons. Resonance spectral bandwidths of 1.9 nm were experimentally measured in both the reflected and transmitted intensities from these structures. Numerical calculations indicate that interference rather than the usual surface plasmon absorption mechanism plays the dominant role in the resonance response when the thickness of the guiding metal layer in the structures is reduced below 10 nm. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118532

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

High-speed and random-access tuning of output wavelengths was achieved in an optical parametric oscillator pumped with an electronically tuned Ti:sapphire laser, which was fully under computer control. The signal and idler wavelengths in 90° phase-matchedKTiOPO4were scanned without mechanical rotation of crystals or mirrors. Signal waves in the range from 1.06 to 1.31 &mgr;m and idler waves in the range from 2.27 to 2.97 &mgr;m accessed in random order by setting the pumping wavelengths between 713 and 923 nm. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118533

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The resonant nonlinear optical response and singlet excited-state dynamics in the thin film of polydithieno (3,2-b; 2′, 3′-d) thiophene are studied by time-resolved degenerate four-wave mixing. Our experimental results, using<1ps excitation at 635 nm, show that bimolecular decay via exciton–exciton annihilation dominates the temporal response at high intensities, thus decreasing the singlet lifetime. The measured rate constant of the singlet annihilation isk2=7.5×10−9cm3/s. Estimates of the singlet-singlet annihilation, exciton diffusion coefficient, and hopping rate are obtained from the measurements. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.118276

出版商:AIP    

年代:1997

数据来源: AIP