Brillouin scattering

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

In Vivo Brillouin Analysis of the Aging Crystalline Lens.

Abstract: Purpose To analyze the age dependence of the longitudinal modulus of the crystalline lens in vivo using Brillouin scattering data in healthy subjects. Methods Brillouin scans were performed along the crystalline lens in 56 eyes from 30 healthy subjects aged from 19 to 63 years. Longitudinal elastic modulus was acquired along the sagittal axis of the lens with a transverse and axial resolution of 4 and 60 μm, respectively. The relative lens stiffness was computed, and correlations with age were analyzed. Results Brillouin axial profiles revealed nonuniform longitudinal modulus within the lens, increasing from a softer periphery toward a stiffer central plateau at all ages. The longitudinal modulus at the central plateau showed no age dependence in a range of 19 to 45 years and a slight decrease with age from 45 to 63 years. A significant intersubject variability was observed in an age-matched analysis. Importantly, the extent of the central stiff plateau region increased steadily over age from 19 to 63 years. The slope of change in Brillouin modulus in the peripheral regions were nearly age-invariant. Conclusions The adult human lens showed no measurable age-related increase in the peak longitudinal modulus. The expansion of the stiff central region of the lens is likely to be the major contributing factor to age-related lens stiffening. Brillouin microscopy may be useful in characterizing the crystalline lens for the optimization of surgical or pharmacological treatments aimed at restoring accommodative power.

On-chip stimulated Brillouin scattering

Abstract: We report the first demonstration of on-chip stimulated Brillouin scattering (SBS). SBS is characterized in a chalcogenide (As 2 S 3 ) photonic chip where the measured Brillouin shift and full-width at half-maximum (FWHM) linewidth are 7.7 GHz and 34 MHz respectively. The measured Brillouin gain coefficient (g B ) is 0.715 x 10 -9 m/W, consistent with the theoretical estimate. Keywords: stimulated Brillouin scattering, on-chip,chalcogenide 1. INTRODUCTION Stimulated Brillouin scattering (SBS) is an inelastic scattering process, which results from the interaction of photons with acoustic phonons in a medium [1]. SBS has been exploited in optical fibers to enable a number of important applications such as Brillouin lasers, slow-light, microwave (MW) generation, optical signal-to-noise ratio (OSNR) monitoring, slow-light based true time delay, opto-mechanical oscillator and tailoring optical forces [2-17] . Recently, SBS was characterized in a photonic crystal fiber (PCF) where the strong optical-acoustic confinement allows efficient SBS process [18, 19]. While there have been several detailed studies, both theoretical and experimental, of SBS in optical fibers, the ability to harness SBS in a chip scale device holds the key to realize light-sound and light-light interaction in an integrated optical structure. Realization of on-chip SBS, however, is challenging because many of the optical materials, commonly used in nonlinear optics, have very low Brillouin scattering cr oss-section and therefore long lengths are required at moderate pump powers. Chalcogenide glass, on the other hand, has very large Kerr nonlinearity [20] and Brillouin gain, which enables SBS realization in short fiber length. In this paper, we report our recent results on SBS generation in a chip scale device [21]. SBS was characterized in a 7 cm long chalcogenide (As

Coherent optical-fibre subscriber line

Abstract: A laboratory bidirectional four-channel broadband coherent-type fibre-optic subscriber line (3.5 km) is reported. The carriers are centre-frequency-stabilised by a ‘heterodyne spectroscope’ and demultiplexed by a tunable heterodyne receiver. In a very special state of the system, BER increases for nonlinear interaction between two counterpropagating narrowband lightwaves because of Brillouin scattering.

Low distortion slow light in flat Brillouin gain spectrum by using optical frequency comb

Abstract: We present a novel method for realizing a slow light with a broadband flat Brillouin gain and low distortion by using an optical frequency comb. We obtained a pump light consisting of 20 discrete line spectra using an optical frequency comb generation technique and a flat SBS gain with a 200 MHz bandwidth. We have realized a large relative pulse delay of 2.46 while suppressing the broadening factor to less than 1.19 for a pulse with a duration of 5.44 ns.

Integrated continuous-wave aluminum nitride Raman laser

Abstract: Wurtzite aluminum nitride (AlN) is known to exhibit six Raman-active optic phonons, making it appealing for Raman lasing. Here, we demonstrate continuous-wave Raman lasers with a low threshold and a high slope efficiency in high quality factor AlN-on-sapphire microrings. Stokes radiations around 1.7–1.8 μm and cascaded operation into 1.9–2.0 μm are identified with a telecom pump. Two types of Stokes lights with distinct Raman shifts and polarizations are recorded via selective excitation of corresponding optic phonons, in accordance with the Raman selection rules in AlN. The observed lasing behavior is satisfactorily accounted for by a theoretical analysis. Our results indicate that AlN-on-sapphire should be promising for integrated nonlinear optics.