Carrier-wave Rabi flopping: role of the carrier-envelope phase

Recently, a dependence of Rabi flopping on the carrier-envelope phase of the exciting laser pulses was predicted theoretically [Phys. Rev. Lett. 89, 127401 (2002)] for excitation of a thin semiconductor film with intense few-cycle pulses. Here, we report corresponding experiments on 50-100-nm thin GaAs films excited with 5-fs pulses. We find a dependence on the carrier-envelope phase arising from the interference of sidebands from the fundamental or the third-harmonic Mollow triplet, respectively, with surface second-harmonic generation.     

Transition between different coherent light-matter interaction regimes analyzed by phase-resolved pulse propagation

We present phase-resolved pulse propagation measurements that allow us to fully describe the transition between several light-matter interaction regimes. The complete range from linear excitation to the breakdown of the photonic bandgap on to self-induced transmission and self-phase modulation is studied on a high-quality multiple-quantum-well Bragg structure. An improved fast-scanning cross-correlation frequency-resolved optical gating setup is applied to retrieve the pulse phase with an excellent signal-to-noise ratio. Calculations using the semiconductor Maxwell-Bloch equations show qualitative agreement with the experimental findings.     

Purcell factor in small metallic cavities

We have studied theoretically the Purcell factor which characterizes a change in the emission rate of an electric or magnetic dipole embedded in the center of a spherical cavity. The main attention is paid to the analysis of cavities with radii small compared to the wavelength. It is shown that the Purcell factor in small metallic cavities varies in a wide range depending on the ratio of the cavity size to the skin depth.     

Anomalous behavior of excitons at light holes in strained (In, Ga)As/GaAs heterostructures

Additional localization of holes due to Coulomb attraction to the electron located in a quantum well is important for light-hole excitons in the heterostructure (In, Ga)As/GaAs. The fine structure of the optical and magneto-optical spectra of these quantum wells is examined in detail with the formation of a “Coulomb well” and deformations taken into account. Fiz. Tverd. Tela (St. Petersburg) 40, 797–799 (May 1998)     

Polariton dispersion of periodic quantum well structures

We studied the polariton dispersion relations of a periodic quantum-well structure with a period in the vicinity of half the exciton resonance wavelength, i.e., the Bragg structure. We classified polariton modes using an approximation of a large number of quantum wells. The polariton effective masses are found to be very small and equal to 10^?3?10^?4 of the free-electron mass.     

Rhenium complexes with π-acetylenic ligands that contain silicon,germanium, and tin

Conclusions A study was made of the reaction of CpRe(CO)₂·THF with acetylenes of type Ph₃MCCPh, where M=Si, Ge, Sn. The previously unknown acetylenic complexes of rhenium CpRe(CO)₂(-Ph₃MCCPh), where M=Si and Ge, were isolated and studied, and it was shown that these complexes can undergo partial rearrangement to compounds with phenylvinylidene ligands.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1124–1126, May, 1979.     

Vinylidene complexes of transition metals : IV. The transfer of the phenylvinylidene ligand from manganese to rhenium. the novel binuclear complex Cp2MnRe(μ-CCHPh)(CO)4

The novel complex Cp₂MnRe(μ-CCHPh)(CO)₄ (I) containing the bridging phenylvinylidene ligand and MnRe bond was obtained in the reaction of CpMn(CCHPh)(CO)₂ with CpRe(CO)₂·THF. Complex I turns into CpRe(CCHPh)(CO)₂ under normal conditions. This is the first example of the transfer of the vinylidene ligand from one transition metal to another.     

Room-temperature single-wavelength optical latching circuits using GaAs bistable devices as logic gates

Room-temperature two-element latching circuits are experimentally demonstrated using GaAs multiple-quantum-well (MQW) nonlinear etalons under single-wavelength bistable operation. Signal power gains of up to 4 and contrast ratios of 10 have been achieved at milliwatt power levels with 1-s pulses, which will allow the construction of more complicated digital optical circuits using diode lasers as the light sources. The problems of applying these nonlinear etalons to fast optical signal processing are also discussed. Numerical simulations show that the gain vanishes as the pulse duration decreases and approaches the carrier lifetime.Jointly with the Physics Department