Topic
Four-wave mixing
About: Four-wave mixing is a research topic. Over the lifetime, 7530 publications have been published within this topic receiving 112702 citations.
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TL;DR: A unified microscopic approach to four-wave mixing (FWM) in semiconductors on an ultrashort time scale is presented and the results explain the dependence of FWM signals on the polarization geometry, especially if biexcitons contribute.
Abstract: We present a unified microscopic approach to four-wave mixing (FWM) in semiconductors on an ultrashort time scale. The theory is valid for resonant excitation in the vicinity of the excitonic resonance and at low densities. The most important many-particle effects, i.e., static and dynamical exciton-exciton interaction as well as biexcitonic effects are incorporated. The internal fields resulting from these interaction processes give rise to pronounced many-particle effects in FWM signals. Our results explain the dependence of FWM signals on the polarization geometry, especially if biexcitons contribute. Time-resolved (TR) FWM experiments show that the diffraction of the interaction induced fields dominate the FWM signals completely. This dominance of the interaction induced field at low temperatures is true regardless of density, detuning, or polarization geometry. While spectrally resolved FWM (-FWM) shows biexcitonic or bound excitonic contributions under various experimental conditions, TR-FWM is always completely delayed, peaking roughly at the dephasing time after both beams passed through. \textcopyright{} 1996 The American Physical Society.
92 citations
TL;DR: A novel approach to coherent nonlinear optical spectroscopy based on two-dimensional femtosecond pulse shaping is introduced, yielding an unprecedented level of control over the interacting fields in nonlinear spectroscopic experiments.
Abstract: A novel approach to coherent nonlinear optical spectroscopy based on two-dimensional femtosecond pulse shaping is introduced. Multiple phase-stable output beams are created and overlapped at the sample in a phase-matched boxcars geometry via two-dimensional femtosecond pulse shaping. The pulse timing, shape, phase, and spectral content within all beams may be specified, yielding an unprecedented level of control over the interacting fields in nonlinear spectroscopic experiments. Heterodyne detection and phase cycling of the nonlinear signal are easily implemented due to the excellent phase stability among all output beams. This approach combines the waveform generation capabilities of magnetic resonance spectroscopy with the wavevector specification and phase matching of nonlinear optical spectroscopy, yielding the control capabilities and signal selectivity of both. Results on four prototype systems are used to illustrate some of the novel possibilities of this method.
91 citations
TL;DR: It is shown that seeding the FWM process overcomes the deleterious effects of group-velocity mismatch and allows efficient conversion into narrow frequency bands in a synchronized two-color picosecond pulse train.
Abstract: We present a fiber-format picosecond light source for coherent anti-Stokes Raman scattering microscopy. Pulses from a Yb-doped fiber amplifier are frequency converted by four-wave mixing (FWM) in normal-dispersion photonic crystal fiber to produce a synchronized two-color picosecond pulse train. We show that seeding the FWM process overcomes the deleterious effects of group-velocity mismatch and allows efficient conversion into narrow frequency bands. The source generates more than 160 mW of nearly transform-limited pulses tunable from 775 to 815 nm. High-quality coherent Raman images of animal tissues and cells acquired with this source are presented.
91 citations
TL;DR: Alternative methods for the calculation of four-wave-mixing signals are reviewed, in which the relevant laser pulses are incorporated into the system Hamiltonian and the driven system dynamics is simulated numerically exactly.
Abstract: “Four-wave-mixing” is the generic name for a family of nonlinear electronic and vibrational spectroscopies. These techniques are widely used to explore dissipation, dephasing, solvation, and interstate coupling mechanisms in various material systems. Four-wave-mixing spectroscopy needs a firm theoretical support, because it delivers information on material systems indirectly, through certain transients, which are measured as functions of carrier frequencies, durations, and relative time delays of the laser pulses. The observed transients are uniquely determined by the three-pulse-induced third-order polarization. There exist two conceptually different approaches to the calculation of the nonlinear polarization. In the standard perturbative approach to nonlinear spectroscopy, the third-order polarization is expressed in terms of the nonlinear response functions. As the material systems become more complex, the evaluation of the response functions becomes cumbersome and the calculation of the signals necess...
91 citations
TL;DR: Numerical simulation shows that this growth in four-wave mixing fields from soliton-soliton collisions can be eliminated through the use of fiber whose dispersion is tapered, either continuously or in steps, in conformity with the fiber loss curve.
Abstract: In a soliton transmission system using lumped amplifiers, pseudo phase matching allows four-wave mixing fields from soliton–soliton collisions to grow uncontrollably and inflict severe penalties. Through numerical simulation, we show that this growth can be eliminated, or at least greatly reduced, through the use of fiber whose dispersion is tapered, either continuously or in steps, in conformity with the fiber loss curve.
91 citations