Topic
Brillouin scattering
About: Brillouin scattering is a research topic. Over the lifetime, 11426 publications have been published within this topic receiving 178306 citations.
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TL;DR: In this paper, the generation of acoustic phonons in optical fibers via electrostriction from coherent optical waves was investigated, and the authors were able to reproduce the experimental spectra found in standard and photonic crystal fibers.
Abstract: We investigate the generation of acoustic phonons in optical fibers via electrostriction from coherent optical waves. Solving the elastodynamic equation subject to the electrostrictive force, we are able to reproduce the experimental spectra found in standard and photonic crystal fibers. We discuss the two important practical cases of forward interaction, dominated by elastic resonances of the fiber, and backward interaction, for which an efficient mechanism of phonon guidance is found. The last result describes the formation of the coherent phonon beam involved in stimulated Brillouin scattering.
73 citations
TL;DR: In this paper, an injection-seeded THz-wave parametric generator pumped by post-amplified emission from a microchip Nd:YAG laser was used to achieve high-sensitive detection with minimum energy of about 80 aJ/pulse (0.8μW at peak) and a large dynamic range of more than 100dB.
Abstract: Intense Terahertz (THz)-wave generation and highly sensitive THz-wave detection were obtained by wavelength conversion with nonlinear optical susceptibility χ(2) of LiNbO3 crystals. Maximum peak output of about 50 kW (5 μJ/pulse) was demonstrated in an injection-seeded THz-wave parametric generator pumped by post-amplified emission from a microchip Nd:YAG laser. Using the sub-nanosecond pulse duration of the laser proposed herein provides effective mitigation of stimulated Brillouin scattering in LiNbO3, producing higher gain for wavelength conversion between near-infrared (near-IR) pump light and THz waves. Monochromatic THz radiation was obtained in the continuous tuning range of 0.7–2.9 THz. Additionally, highly sensitive THz-wave detection was demonstrated based on up-conversion from THz waves to near-IR light as well as efficient THz-wave generation. The signal generated with non-collinear phase-matching condition showed spectroscopic detection on the screen apart from the LiNbO3 crystal. Highly sensitive detection with minimum energy of about 80 aJ/pulse (0.8 μW at peak) and a large dynamic range of more than 100 dB were achieved in this experiment.
73 citations
TL;DR: Two novel bandwidth efficient pump-dithering Stimulated Brillouin Scattering suppression techniques are introduced that employ a frequency-hopped chirp and an RF noise source to impart phase modulation on the pumps of a two pump Fiber Optical Parametric Amplifier (FOPA).
Abstract: Two novel bandwidth efficient pump-dithering Stimulated Brillouin Scattering (SBS) suppression techniques are introduced. The techniques employ a frequency-hopped chirp and an RF noise source to impart phase modulation on the pumps of a two pump Fiber Optical Parametric Amplifier (FOPA). The effectiveness of the introduced techniques is confirmed by measurements of the SBS threshold increase and the associated improvements relative to the current state of the art. Additionally, the effect on the idler signal integrity is presented as measured following amplification from a two pump FOPA employing both techniques. The measured 0.8 dB penalty with pumps dithered by an RF noise source, after accruing 160ps/nm of dispersion with 38 dB conversion gain in a two-pump FOPA is the lowest reported to date.
72 citations
TL;DR: It is demonstrated that SBS pump depletion leads to amplitude response fluctuations, as well as increasing the insertion loss of the phase shifter, which is a record for integrated devices, along with 240° continuously tunable phase shift.
Abstract: We present the first microwave photonic phase shifter using stimulated Brillouin scattering (SBS) on-chip. The unique ability of SBS to generate both narrowband gain and loss resonances allows us to achieve low ±1.5 dB amplitude fluctuations, which is a record for integrated devices, along with 240° continuously tunable phase shift. Contrary to previous SBS-based approaches, the phase shift tuning mechanism relies on tuning the power, not the frequency, of two SBS pumps, making it more suited to on-chip implementations. We finally demonstrate that SBS pump depletion leads to amplitude response fluctuations, as well as increasing the insertion loss of the phase shifter. Advantageously, shorter integrated platforms possess higher pump depletion thresholds compared to long fibers, thus offering greater potential for reducing the insertion loss.
72 citations
TL;DR: In this article, a strong relaxation mode was observed in the paraelectric phase of barium titanate (BaTiO3) single crystals by Brillouin scattering study and was found to correlate with the softening of the longitudinal acoustic mode and the increase in the hypersonic damping.
Abstract: A strong relaxation mode was observed in the paraelectric phase of barium titanate (BaTiO3) single crystals by Brillouin scattering study and was found to correlate with the softening of the longitudinal acoustic mode and the increase in the hypersonic damping. These observations support the existence of polar percursors and their electrostrictive coupling with the strain caused by the acoustic waves, consistent with former studies evidencing off-centered Ti ions in the high-symmetry cubic phase. A critical slowing down has been clearly observed in the vicinity of the cubic-tetragonal phase transition, indicating order-disorder component contributes to the phase transition of BaTiO3.
72 citations