摘要:

The cause of remarkably strong photoluminescence (PL) intensity from (110) surfaces ofn‐type InP was investigated byinsitumeasurements of PL intensity in a vacuum of 4×10−7Torr and in various ambients. The surface cleaved in the vacuum showed about 10 times lower intensity than that for the surface cleaved in air. The strong PL intensity cleaved in air was ascribed to a reduction of surface recombination velocity due to adsorption of H2O and/or O2molecules onto the intrinsic surface. The strong PL intensity for surfaces cleaved in air, O2, and wet N2were more or less unstable and decreased under photoexcitation. Normalized surface recombination velocity for the surface cleaved in air was &zgr;≲1, which was much less than that for GaAs (&zgr;≳10).

ISSN:0003-6951    

DOI:10.1063/1.90829

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Short low‐energy pulses of laser light have been used to switch spots on a liquid crystal (LC) through a coupled photoconductive film of glow‐discharge‐produced amorphous Si (GD/a‐Si). The a‐Si responds rapidly to a light pulse, yet retains sufficient photoconductivity in the slow portion of the decay to match the slower response time of the LC. Spots have been written with laser pulses 10 &mgr;s long, about 10−3the response time of the LC, and with a pulse energy of 1–10 &mgr;J/cm2, less than 10−4the energy required for thermal writing.

ISSN:0003-6951    

DOI:10.1063/1.90830

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

An electro‐optic microwave modulator generating frequency‐swept sidebands 26–31 GHz offset from a CO2laser carrier is described. Resonant enhancement of the modulating field allows as low as 8‐mW microwave drive power. Electronic tuning of the resonances by a ferrite phase shifter inside the cavity increases the FWHM modulation bandwidth from 140 MHz (untuned) to 4 GHz.

ISSN:0003-6951    

DOI:10.1063/1.90831

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Cross‐correlation measurements of the cw double mode‐locked dye laser are described for two different cases, showing that the two pulse trains are highly synchronized. A direct display of the pulse shape at the longer wavelength resulted for the first case, in which a short primary pulse was generated along with a much longer incompletely mode‐locked secondary pulse. For the second case, both pulse trains were completely mode‐locked and short. In each case, the jitter between the two pulse trains was less than 1.6 ps and there was zero delay between the two pulses.

ISSN:0003-6951    

DOI:10.1063/1.90832

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

A resonantly enhanced phase‐conjugate 10.6‐&mgr;m signal has been generated in the saturable absorber SF6. Direct evidence of aberration correction is shown through the use of far‐field photographs taken with a pyroelectric vidicon camera. Reflection coefficients of 7% have been achieved in a few Torr of SF6for a 2‐cm interaction length.

ISSN:0003-6951    

DOI:10.1063/1.90833

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

It has generally been accepted that accurate results may be obtained using the scalar‐wave approach to solve problems dealing with inhomogeneous multimode guided‐wave structures. The problem of the applicability of the scalar‐wave approach to obtain wave propagation characteristics in single‐mode fiber or integrated optical circuit guides with inhomogeneous index profiles is examined in this paper. It is shown that if certain limiting conditions are satisfied, the scalar‐wave approach will yield valid results for single‐mode structures. These limiting conditions are usually satisfied by many practical single‐mode inhomogeneous fibers or IOC structures.

ISSN:0003-6951    

DOI:10.1063/1.90834

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Phase conjugation by nonlinear mixing using local gain saturation of a Nd : YAG laser has been demonstrated. Since the laser itself is used as a nonlinear conjugator, no additional nonlinear medium is needed. In principle, any laser can be used for this purpose since laser gain saturation is inherent to all lasers. The maximum conversion efficiency measured was 0.1%.

ISSN:0003-6951    

DOI:10.1063/1.90835

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

We have established the viability of coherent Raman techniques in the study of acoustic phonon excitations. Using the Raman‐induced Kerr effect scheme, we have obtained the Brillouin spectrum of CS2. The nonlinear polarization in this case is so large that the effects of Stokes gain and anti‐Stokes loss must be included in the theoretical interpretation of the spectrum.

ISSN:0003-6951    

DOI:10.1063/1.90836

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

We report a pulsed‐dye‐laser optoacoustic spectroscopy technique for sensitive measurements of weak absorption spectra of liquids. We have used this technique to measure the weak visible absorption band of benzene near 607 nm, due to the sixth harmonic of the C‐H stretch. We obtain a signal‐to‐noise ratio exceeding 102at the absorption peak. We estimate that with improved data handling, absorption features as small as 10−7cm−1should be detectable in liquids. This opens up new possibilities of trace‐constituent detection and pollution monitoring in the liquid phase.

ISSN:0003-6951    

DOI:10.1063/1.90837

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Recent advances in the development of synchronously mode‐locked dye‐laser systems have permitted the first low‐power measurement of the time‐resolved dephasing dynamics of a Raman active molecular vibration. Excitation and delayed probing of the coherent ensemble of vibrators is accomplished with the help of synchronized picosecond pulse trains from two independently tunable mode‐locked dye lasers. A new probe technique, based on a gain measurement, is employed that provides a signal that scales linearly with the coherent vibrational amplitude. We demonstrate this technique with the first measurement of the dephasing dynamics of the normal mode (656.5 cm−1) of CS2in the liquid state. An exponential decay with time constant 20±1 psec is obtained for the isotropic component of the coherent scattering.

ISSN:0003-6951    

DOI:10.1063/1.90838

出版商:AIP    

年代:1979

数据来源: AIP