scholarly journals Stimulated Brillouin gain spectroscopy in a confined spatio-temporal domain (30 μm, 170 ns)

2020 ◽  
Vol 89 (3) ◽  
pp. 30701
Author(s):  
Lionel Djadaojee ◽  
Albane Douillet ◽  
Jules Grucker
Keyword(s):  
Brillouin Scattering ◽  
Test Sample ◽  
Gain Spectrum ◽  
Acoustic Properties ◽  
Transient Phenomena ◽  
Temporal Domain ◽  
Spatio Temporal ◽  
Brillouin Gain ◽  
Stimulated Brillouin ◽  
Different Sources

The Brillouin gain spectrum of a test sample (liquid acetone at room temperature) on scales simultaneously confined in space (~30 μm) and time (~170 ns) is reported. This is done using a pulsed stimulated Brillouin scattering gain spectrometer in a θ ≈ 90° crossing beam configuration. After having identified and corrected for different sources of background signals, we obtained a Brillouin gain spectrum allowing an accurate measurement (MHz range) of the Brillouin frequency (few GHz). This is of interest for probing acoustic properties of transparent media subjected to repetitive fast transient phenomena on small length scales.

scholarly journals Stimulated Brillouin Scattering Enhanced Fibers for Narrow-Band Filtering by Tailoring Brillouin Gain Spectrum

2017 ◽  
Vol 9 (6) ◽  
pp. 1-11
Author(s):  
Zhen Guo ◽  
Changjian Ke ◽  
Chen Xing ◽  
Yibo Zhong ◽  
Guo Yin ◽  
...  
Keyword(s):  
Narrow Band ◽  
Brillouin Scattering ◽  
Stimulated Brillouin Scattering ◽  
Gain Spectrum ◽  
Brillouin Gain ◽  
Stimulated Brillouin

scholarly journals Fast Measurement of Brillouin Frequency Shift in Optical Fiber Based on a Novel Feedforward Neural Network

Photonics ◽  
2021 ◽  
Vol 8 (11) ◽  
pp. 474
Author(s):  
Fen Xiao ◽  
Mingxing Lv ◽  
Xinwan Li
Keyword(s):  
Neural Network ◽  
Optical Fiber ◽  
Frequency Shift ◽  
Brillouin Scattering ◽  
Principal Component ◽  
Feedforward Neural Network ◽  
Gain Spectrum ◽  
Fiber Sensors ◽  
Brillouin Gain ◽  
Distributed Optical Fiber

Brillouin scattering-based distributed optical fiber sensors have been successfully employed in various applications in recent decades, because of benefits such as small size, light weight, electromagnetic immunity, and continuous monitoring of temperature and strain. However, the data processing requirements for the Brillouin Gain Spectrum (BGS) restrict further improvement of monitoring performance and limit the application of real-time measurements. Studies using Feedforward Neural Network (FNN) to measure Brillouin Frequency Shift (BFS) have been performed in recent years to validate the possibility of improving measurement performance. In this work, a novel FNN that is 3 times faster than previous FNNs is proposed to improve BFS measurement performance. More specifically, after the original Brillouin Gain Spectrum (BGS) is preprocessed by Principal Component Analysis (PCA), the data are fed into the Feedforward Neural Network (FNN) to predict BFS.

THREE-DIMENSIONAL SIMULATIONS OF STIMULATED BRILLOUIN SCATTERING WITH FOCUSED GAUSSIAN BEAMS

1996 ◽  
Vol 05 (02) ◽  
pp. 387-408 ◽  
Author(s):  
T.R. MOORE ◽  
R.W. BOYD
Keyword(s):  
Pump Wave ◽  
Focal Point ◽  
Brillouin Scattering ◽  
Three Dimensional ◽  
Stokes Wave ◽  
Gaussian Beams ◽  
Spontaneous Noise ◽  
Brillouin Gain ◽  
Dimensional Simulation ◽  
Stimulated Brillouin

We report on a detailed investigation of the process of SBS with focused Gaussian beams via a three-dimensional simulation of the SBS process that includes spontaneous noise. We show that spontaneous noise present at points other than where the initiation of SBS occurs does not significantly affect the Stokes wave. The effects on the Stokes beam of modes not present in the pump wave (nonconjugate modes) are investigated and it is found that the phase of a given Stokes mode is affected by the presence of other modes, a process termed phase pulling. We also show that for a focused Gaussian beam the Brillouin gain parameter does not increase linearly with increased pump power once SBS threshold is reached; rather, above threshold the SBS process resembles a reverse saturable absorber for the pump wave at any point. between the entrance to the medium and the focal point of the pump beam.

Characterisation of Liquid Brillouin Media at 532 nm

1997 ◽  
Vol 06 (01) ◽  
pp. 69-79 ◽  
Author(s):  
D. C. Jones
Keyword(s):  
Brillouin Scattering ◽  
Optical Breakdown ◽  
Gain Coefficient ◽  
High Gain ◽  
Four Wave Mixing ◽  
Wave Mixing ◽  
Phase Conjugate ◽  
Brillouin Gain ◽  
Stimulated Brillouin ◽  
532 Nm

A number of transparent liquids have been evaluated for use in stimulated Brillouin scattering at 532 nm. Measurements were made of frequency shift, SBS threshold, reflectivity and optical breakdown properties. It was found that the alkanes, and in particular n-pentane, performed well and measurements were made of Brillouin gain coefficient and phonon lifetimes. It is suggested that these liquids are promising candidates for use in self-pumped phase conjugate mirrors, high gain Brillouin amplifiers and four-wave mixing mirrors.

Enhanced levels of stimulated Brillouin reflectivity from non-Maxwellian plasmas

2007 ◽  
Vol 73 (2) ◽  
pp. 159-166 ◽  
Author(s):  
M.S. BAWA'ANEH ◽  
T.J.M. BOYD
Keyword(s):  
Experimental Data ◽  
Acoustic Noise ◽  
Brillouin Scattering ◽  
Stimulated Brillouin Scattering ◽  
Temperature Gradients ◽  
Target Plasma ◽  
Ion Acoustic ◽  
Brillouin Gain ◽  
Stimulated Brillouin

Abstract.A model that counts for temperature gradients in the target plasma, which leads to higher ion acoustic noise and enhanced levels of stimulated Brillouin scattering (SBS) gain and SBS reflectivity, has been adopted. Enhanced Brillouin gain leading to higher SBS reflectivity levels has been computed for non-homogeneous, non-Maxwellian plasmas. SBS reflectivity levels obtained are higher than those predicted by linear convective gain theory by several orders of magnitude and coincide with the high values of experimental data known in literature, which could not be interpreted by the linear convective gain theory.

INFLUENCE OF PIEZOELECTRICITY AND MAGNETIC FIELD ON STIMULATED BRILLOUIN SCATTERING IN III–V SEMICONDUCTORS

2006 ◽  
Vol 15 (04) ◽  
pp. 465-479 ◽  
Author(s):  
M. SINGH ◽  
P. AGHAMKAR ◽  
N. KISHORE ◽  
PRANAY K. SEN
Keyword(s):  
Magnetic Field ◽  
Brillouin Scattering ◽  
Phase Conjugation ◽  
Stimulated Brillouin Scattering ◽  
Gain Coefficient ◽  
Analytical Investigation ◽  
Magnetostatic Field ◽  
Brillouin Gain ◽  
Nonlinear Devices ◽  
Stimulated Brillouin

Using electromagnetic treatment, a detailed analytical investigation of stimulated Brillouin scattering (SBS) has been made for a semiconducting crystal in the presence of an external magnetostatic field. The effect of piezoelectricity (β) and magnetic field [Formula: see text] has been introduced through equation of motion of lattice vibration and Lorentz force, respectively. The analysis is applied to both cases viz. non-piezoelectric (β = 0) and piezoelectric (β ≠ 0) in the absence (B0 =0) and the presence (B0 ≠ 0) of external magnetostatic field. The numerical estimates are made for n-type InSb crystals, taken as representative III–V semiconductor, duly shined upon by pulsed 10.6 μm CO 2 laser. The inclination of applied magnetostatic field with respect to the direction of propagation of pump beam is found to augment the gain coefficient for the onset of stimulated Brillouin scattering. Moreover, the SBS gain coefficient increases with increasing scattering angle and results in a maximum value for the backscattered mode. The backward Brillouin gain is found to be nearly 104 times larger than forward gain when β ≠ 0 and B0 = 10T. The analysis also suggests the possibility of observing optical phase conjugation reflectivity as high as 106 in the weakly piezoelectric doped semiconductors with moderate magnetostatic field. The numerical estimation suggests that piezoelectric doped III–V semiconductors in the presence of magnetic field are candidate materials for fabrication of cubic nonlinear devices.

STIMULATED BRILLOUIN SCATTERING IN n-TYPE III–V PIEZOELECTRIC SEMICONDUCTORS

2001 ◽  
Vol 10 (02) ◽  
pp. 265-278 ◽  
Author(s):  
PRADEEP K. GUPTA ◽  
PRANAY K. SEN
Keyword(s):  
Brillouin Scattering ◽  
Stimulated Brillouin Scattering ◽  
Damage Threshold ◽  
Qualitative Behavior ◽  
Pump Field ◽  
Coupled Mode ◽  
Type Semiconductor ◽  
Brillouin Gain ◽  
Piezoelectric Semiconductors ◽  
Stimulated Brillouin

Based upon the hydrodynamic model of an one-component semiconductor plasma, a detailed analytical study of stimulated Brillouin scattering (SBS) processes in a doped weakly piezoelectric semiconductor has been made following the coupled mode approach. The nonlinear effective polarization and the corresponding third-order optical susceptibility at Stokes frequency for the SBS processes are obtained. The analysis deals with the qualitative behavior of threshold pump electric field required for the onset of SBS and the Brillouin gain with respect to the doping concentration well above threshold. Numerical analysis has been made for n-type InSb crystal duly irradiated by a nanosecond pulsed 10.6 μm CO 2 laser. The influence of piezoelectric properties of the crystal medium on both threshold pump field and Brillouin gain has been explored and it is found that SBS with significant gain at lower threshold pump field could be achieved in the weakly piezoelectric moderately doped n-type semiconductor. The Brillouin gain is noted to be significantly large only over a very narrow doping range. The theoretical analysis shows that the doped III–V semiconductors have a good potentiality in the fabrication of SBS based phase conjugate mirrors with high reflectivity well below the optical damage threshold.

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