摘要:

Calculated and experimental results are presented for coupling bulk electromagnetic waves to surface electromagnetic waves using overcoated gratings at 118.8 &mgr;. A coupling efficiency of 8.7% is reported.

ISSN:0003-6951    

DOI:10.1063/1.93393

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

The one‐phonon and two‐phonon Raman spectra have been measured in the temperature range 20–900 °C. The rate of decrease of the normalized frequencies with increase of temperature for the zone center, TO atLand TA atX, is 5.4×10−5/°C, while for TO atXand TA atLis lower, being 3.6×10−5/°C. We have also found that the relative intensity of Stokes and anti‐Stokes components of the &Ggr;‐point optical phonon deviates significantly from the value involving only the phonon occupation number, particularly at high temperatures. The decrease of the &Ggr;25′phonon from 521 cm−1at 20 °C to 493 cm−1at 900 °C should provide an unambiguous determination of the surface temperature due to laser heating.

ISSN:0003-6951    

DOI:10.1063/1.93394

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

Carrier heating effects are shown to contribute significantly to temperature sensitivity of threshold current in InGaAsP 1.3‐&mgr;m lasers. For the empirical expressionJth∼J0 exp(T/T0), a single value ofT0=90 K describes the data for 100 K<TL<350 K whenTis taken to be the carrier temperature. This result is in contrast to the variation inT0from 90 to 60 K found whenTis taken to be the lattice temperature.

ISSN:0003-6951    

DOI:10.1063/1.93395

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

Using a high‐resolution electron‐impact energy‐loss spectrometer we have measured the energy‐loss spectra of electrons scattered near the forward direction from HgCl2and HgBr2, for incident energies of 200 eV and energy‐loss between 4 and 14 eV. Under these conditions the energy‐loss spectra correspond closely to optical‐absorption spectra. In addition to the well known1&Pgr;uand1∑+uabsorption bands, we observe many new energy‐loss processes beginning at 7.9 eV in HgBr2and 8.60 eV in HgCl2. The relative cross sections and energies of these processes are in excellent agreement with those inferred as being necessary to account for discharge and fluorescence measurements ine‐beam sustained mercuric bromide lasers.

ISSN:0003-6951    

DOI:10.1063/1.93396

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

The third order nonlinear susceptibility &khgr;(3)caused by band nonparabolicity is investigated for gallium arsenide‐gallium aluminum arsenide superlattices. Optimization of well width, superlattice periodicity, and barrier height give rise to large nonparabolicities which produce nonlinear susceptibilities comparable to those found in indium antimonide and at least two orders of magnitude larger than bulk gallium arsenide.

ISSN:0003-6951    

DOI:10.1063/1.93397

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

Liquid phase epitaxial grown Cd‐doped InGaAsP/InP double‐heterostructure stripe lasers were found to yield very high external differential quantum efficiency, &eegr;ext∼74% in relatively long cavity lasers compared to that of our Zn‐doped ones. Since Cd was found to diffuse only slightly into the active layer, the high &eegr;extas well as the lower threshold current in the Cd‐doped lasers are attributed to lower concentration of nonradiative recombination centers. The broad area lasers have lower &eegr;extthan the respective stripe lasers. Moreover, &eegr;extis insensitive to the heat sink temperature in the range 20–70 °C in the stripe lasers while it drops considerably in the broad area ones.

ISSN:0003-6951    

DOI:10.1063/1.93398

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

Bistability due to a second‐order dispersive nonlinearity in a Fabry–Perot resonator is studied. The experiments are performed on a nonlinear transmission line resonator. Nonlinear resonance curves, bistability as well as instabilities, and the generation of harmonics are observed. The theoretical treatment of bistability is based upon a nonlinear dispersion relation as derived from an inspection of two interacting harmonics or, in a second approach, of propagating solitons.

ISSN:0003-6951    

DOI:10.1063/1.93399

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

Continuous wave GaAlAs semiconductor laser arrays are reported to emit 585‐mW/facet cw optical output power at room temperature. The lasers operate over 100 °C with output powers in excess of 200 mW/facet cw. Laser thresholds are as low as 130 mA, differential quantum efficiencies exceed 60% for some devices, and very high total power conversion efficiencies of over 20% are observed.

ISSN:0003-6951    

DOI:10.1063/1.93382

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

A 40‐mJ ArF* laser with pulse duration ∼10 ps and spatial and spectral properties close to the transform limits is described. Substantial extraction of the available energy from the final amplifier is demonstrated, a fact providing direct evidence against the presence of significant nonlinear losses in the amplifying medium up to an intensity of ∼1 GW/cm.2

ISSN:0003-6951    

DOI:10.1063/1.93383

出版商:AIP    

年代:1982

数据来源: AIP

摘要:

The first overtone vibration‐rotation lines of hydrogen fluoride have been observed around the wavelength region of 1.3 &mgr;m by using a current‐tunable InGaAsP semiconductor laser operated at the temperature range from −24 °C to +24 °C. The laser frequency has been locked to one of theR‐branch lines with the stability of 2.0×10−10≥&sgr;(2,&tgr;)≥7.9×10−11at the averaging time between 1 and 240 s.

ISSN:0003-6951    

DOI:10.1063/1.93384

出版商:AIP    

年代:1982

数据来源: AIP