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.

Portraying polarization state of terahertz pulse generated by a two-color laser field in air.

Abstract: By using an electro-optic sampling technique, the instantaneous field vector of the terahertz (THz) pulse generated by mixing a near-IR femtosecond pulse and its second harmonic in air has been studied. The polarization of the investigated THz pulse is found to be predominantly linear and orthogonal to that of the second harmonic, revealing the major role of χ(3)xyxy during the four-wave mixing process.

Wavelength-agile high-power sources via four-wave mixing in higher-order fiber modes.

Abstract: Frequency doubling of conventional fiber lasers in the near-infrared remains the most promising method for generating integrated high-peak-power lasers in the visible, while maintaining the benefits of a fiber geometry; but since the shortest wavelength power-scalable fiber laser sources are currently restricted to either the 10XX nm or 15XX nm wavelength ranges, accessing colors other than green or red remains a challenge with this schematic. Four-wave mixing using higher-order fiber modes allows for control of dispersion while maintaining large effective areas, thus enabling a power-scalable method to extend the bandwidth of near-infrared fiber lasers, and in turn, the bandwidth of potential high-power sources in the visible. Here, two parametric sources using the LP0,7 and LP0,6 modes of two step-index multi-mode fibers are presented. The output wavelengths for the sources are 880, 974, 1173, and 1347 nm with peak powers of 10.0, 16.2, 14.7, and 6.4 kW respectively, and ~300-ps pulse durations. The efficiencies of the sources are analyzed, along with a discussion of wavelength tuning and further power scaling, representing an advance in increasing the bandwidth of near-infrared lasers as a step towards high-peak-power sources at wavelengths across the visible spectrum.

Efficient anti-Stokes Raman conversion in collimated beams

Abstract: We have demonstrated 10% energy-conversion efficiency of 0.5-nsec FWHM laser pulses at 248 to 225 nm by an anti-Stokes process in hydrogen, using collimated (unfocused) laser beams. To accomplish this, we simultaneously seeded the Raman cell with a Stokes pulse that was 2–6% as intense as the pump at the phase-matching angle with respect to the pump beam axis. Under these conditions, a fully transient plane-wave calculation suggests that 44% energy-conversion efficiency is possible. Phase-front imperfections on the pump and Stokes beams are thought to limit the observed conversion efficiency. We present a simple model describing the effect of phase distortion on anti-Stokes production that agrees with our observations. Experimentally observed dynamic effects are in good agreement with theoretical predictions.

Optical parametric gain and bandwidth in highly nonlinear tellurite hybrid microstructured optical fiber with four zero-dispersion wavelengths.

Abstract: The parametric amplification gain and bandwidth in highly nonlinear tellurite hybrid microstructured optical fiber (HMOF) are simulated based on four wave mixing process. The fiber core and cladding materials are made of TeO2–Li2O–WO3–MoO3–Nb2O5 and TeO2–ZnO–Na2O–P2O5 glass, respectively. The fiber has four zero-dispersion wavelengths and the chromatic dispersion is flattened near the zero-dispersion wavelengths. A broad gain bandwidth as wide as 1200 nm from 1290 to 2490 nm can be realized in the near infrared window by using a tellurite HMOF as short as 25 cm.