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.

Collimated blue light generated by four-wave mixing in Rb vapour

Abstract: We investigate frequency up-conversion of low power cw resonant radiation in Rb vapour as a function of various experimental parameters. We present evidence that the process of four wave mixing is responsible for unidirectional blue light generation and that the phase matching conditions along a light-induced waveguide determine the direction and divergence of the blue light. Velocity-selective excitation to the 5D level via step-wise and two-photon processes results in a Doppler-free dependence on the frequency detuning of the applied laser fields from the respective dipole-allowed transitions. Possible schemes for ultraviolet generation are discussed.

Fiber four-wave mixing in multi-amplifier systems with nonuniform chromatic dispersion

Abstract: Fiber fiber-wave mixing (FWM) is studied for multichannel multi-amplifier systems composed of short fibers with different zero-dispersion wavelength. An analytical expression describing FWM in these systems is derived. Using the expression, crosstalk is calculated for various combinations of fiber lengths, which are selected according to a random function, and allowable fiber input power is evaluated. The results show that the allowable input power for nonuniform dispersion is larger than that for uniform dispersion by several dB, depending on system conditions. >

Generation of a 160-GHz transform-limited pedestal-free pulse train through multiwave mixing compression of a dual-frequency beat signal

Abstract: We report the experimental generation of a 160-GHz picosecond pulse train at 1550 nm, using multiple four-wave mixing temporal compression of an initial dual-frequency beat signal in the anomalous-dispersion regime of a nonzero dispersion-shifted fiber. Complete intensity and phase characterizations of the pulse train were carried out by means of a frequency-resolved optical gating technique, showing that 1.27-ps transform-limited pedestal-free Gaussian pulses were generated.

Second-harmonic-assisted four-wave mixing in chip-based microresonator frequency comb generation

Abstract: Simultaneous Kerr comb formation and second-harmonic generation with on-chip microresonators can greatly facilitate comb self-referencing for optical clocks and frequency metrology. Moreover, the presence of both second- and third-order nonlinearities results in complex cavity dynamics that is of high scientific interest but is still far from being well-understood. Here, we demonstrate that the interaction between the fundamental and the second-harmonic waves can provide an entirely new way of phase matching for four-wave mixing in optical microresonators, enabling the generation of optical frequency combs in the normal dispersion regime under conditions where comb creation is ordinarily prohibited. We derive new coupled time-domain mean-field equations and obtain simulation results showing good qualitative agreement with our experimental observations. Our findings provide a novel way of overcoming the dispersion limit for simultaneous Kerr comb formation and second-harmonic generation, which might prove to be especially important in the near-visible to visible range where several atomic transitions commonly used for the stabilization of optical clocks are located and where the large normal material dispersion is likely to dominate. Tuning the interactions between fundamental and second-harmonic waves can facilitate measurements of atomic-based optical clocks.On-chip microresonators have recently been developed that convert single-frequency laser sources into broadband, regularly spaced spectra — frequency combs — for portable metrology applications. Xiaoxiao Xue from Tsinghua University in China, Andrew Weiner from Purdue University in the United States, and colleagues have now found a way to convert a fraction of the frequency lines from a wideband comb into second-harmonic light that can potentially benchmark comb accuracy. The researchers located the resonant modes for second-harmonic generation in a silicon nitride microring using an adjustable infrared laser and then swept the microresonator over a range of frequencies to produce a comb. They identified a nonlinear coupling mechanism that may improve comb generation in the near-visible and visible spectral regions, where many atomic transitions in optical clocks occur.

Saturable absorption, wave mixing, and phase conjugation with bacteriorhodopsin.

Abstract: Bacteriorhodopsin exhibits strong nonlinear and saturation behavior with very low light intensities (~10 mW/cm(2)). A model and an experimental study of the saturation are described. Four-wave mixing experiments are used for obtaining phase conjugation and information on the holographic resolution of the material. Two kinds of samples were prepared and used in the experiments: films of bacteriorhodopsin in a solid polyvinylalcohol (polymer) matrix and in water.