Brillouin scattering

About: Brillouin scattering is a research topic. Over the lifetime, 11426 publications have been published within this topic receiving 178306 citations.

Thermal Relaxation and Brillouin Scattering in Liquids.

Abstract: Weak coupling of internal degrees of freedom of molecules to the translational degrees of freedom of a fluid results in additional modes of motion for density fluctuations. These new modes affect the spectral distribution of light scattered by density fluctuations so that the Landau-Placzek ratio is not satisfied. The case of thermal relaxation with a single relaxation time is worked out in detail. Formulas for the spectral distribution of the scattered light, for the ratio of the intensities of the central (Rayleigh) to the Brillouin components and for the phonon velocity are derived and applied to carbon disulfide and carbon tetrachloride. The data for carbon tetrachloride are shown to be inconsistent with the single relaxation time model for thermal relaxation.

Broad-band RF photonic phase shifter based on stimulated Brillouin scattering and single-sideband modulation

Abstract: We introduce a novel RF photonic phase shifter based on Brillouin signal processing of optical single-sideband signals. The theoretical fundamentals of the design are explained and the main factors influencing its performance are analyzed. This phase shifter provides broad operational bandwidth and a full 360/spl deg/ phase-shift tuning range with a single external electrical control. A prototype of the phase shifter with 18-GHz bandwidth and full 360/spl deg/ tuning range is experimentally demonstrated.

32-km distributed temperature sensor based on Brillouin loss in an optical fiber

Abstract: We present a novel distributed temperature sensor that uses the temperature dependence of the frequency at which the loss is maximized in the interaction between a cw laser and a pulsed laser. With a 32-km sensing length, a temperature resolution of 1°C has been achieved; it is also shown that a spatial resolution of 5 m may be obtained.

Optically controlled slow and fast light in optical fibers using stimulated Brillouin scattering

Abstract: We demonstrate a method to achieve an extremely wide and flexible external control of the group velocity of signals as they propagate along an optical fiber. This control is achieved by means of the gain and loss mechanisms of stimulated Brillouin scattering in the fiber itself. Our experiments show that group velocities below 71000km∕s on one hand, well exceeding the speed of light in vacuum on the other hand and even negative group velocities can readily be obtained with a simple benchtop experimental setup. We believe that the fact that slow and fast light can be achieved in a standard single-mode fiber, in normal environmental conditions and using off-the-shelf instrumentation, is very promising for a future use in real applications.

Elasticity of coesite

Abstract: The single-crystal elastic constants of SiO2, coesite (monoclinic, C2/c), have been determined from Brillouin scattering measurements on a 100-μm crystal. The elastic constants inferred from acoustic velocities for 80 different propagation directions are (in units of Mbar) c11 = 1.608, c22 = 2.304, c33 = 2.316, c44 = 0.678, c55 = 0.733, c66 = 0.588, c12 = 0.821, c13 = 1.029, c15 = −0.362, c23 = 0.356, c25 = 0.026, c35 = −0.393, and c46 = 0.099. This experimental technique provides a method of determining single-crystal elastic properties for materials such as high-pressure phases that are not available in sufficiently large sizes for ultrasonic measurements.