Cavity length matching and optical resonances in a Raman laser with the multimode pump source

2017 ◽  
Vol 42 (23) ◽  
pp. 4824 ◽  
Author(s):  
Ruslan V. Chulkov ◽  
Vasyli Y. Markevich ◽  
Ahmed Y. Alyamani ◽  
Evgenii A. Cheshev ◽  
Valentin A. Orlovich
Keyword(s):  
Cavity Length ◽  
Raman Laser ◽  
Optical Resonances ◽  
Pump Source

scholarly journals Statistics of pulse enrgy fluctuations in a solid-state Raman laser

2020 ◽  
Vol 56 (4) ◽  
pp. 459-469
Author(s):  
R. V. Chulkov ◽  
O. P. Korozhan ◽  
V. A. Orlovich
Keyword(s):  
Conversion Efficiency ◽  
Frequency Conversion ◽  
Cavity Length ◽  
Optical Feedback ◽  
Raman Laser ◽  
Spatial Inhomogeneity ◽  
Raman Frequency ◽  
Optical Length ◽  
Optical Pump ◽  
Nanosecond Pulses

In this paper, we present the results of the study of the statistics of pulse energy fluctuations in a Raman laser under optical pump by the multimode nanosecond pulses. A system of coupled differential equations for slowly varying envelopes of the pump field and first three Stokes lines was integrated numerically with taking into account spatial inhomogeneity of the pump beam, spontaneous noise, and optical feedback. Data of the numerical simulation revealed a sharp increase in the fluctuation amplitude in the nonlinear regime of Raman frequency conversion when the optical length of the Raman cavity was matched with the cavity length of the multimode pump laser. At a mean 1st Stokes conversion efficiency of 3.5–3.8 %, the calculations showed an increase in the coefficient of variation (CV) of a random value from 9 % to 118 %. In the linear regime of Raman frequency conversion, when the conversion efficiency was 0.2–0.03 %, a further increase in the CV value up to 270–500 % was predicted. It is also numerically shown that the fluctuation statistics under the conditions of the cavity length matching is essentially non-Gaussian and described by the L-type probability density distributions (PDDs) with long tails and maxima located near zero. The numerical data were quantitatively confirmed by an experiment for a Raman laser on a barium nitrate crystal operated near the Raman threshold, when the 1st Stokes conversion efficiency did not exceed 0.3 %. A Raman cavity was formed by two flat mirrors providing a double-pass pump configuration. The Raman laser was excited by the linearly polarized frequency-doubled radiation of a Q-switched Nd:YAG laser generating multimode pulses with a duration of 7–8 ns. A Raman laser operating regime characterized by the hyperexponential PDDs with CVs reaching 480 %, which is 2–2.5 times higher than those observed earlier for the single-pass conditions of stimulated Raman scattering, was realized.

scholarly journals Superluminal Raman laser with enhanced cavity length sensitivity

2019 ◽  
Vol 27 (21) ◽  
pp. 29738 ◽  
Author(s):  
Zifan Zhou ◽  
Minchuan Zhou ◽  
Selim M. Shahriar
Keyword(s):  
Cavity Length ◽  
Raman Laser

Semiconductor Raman laser with resonator film transparent to pump light

1991 ◽  
Vol 138 (6) ◽  
pp. 396 ◽  
Author(s):  
K. Suto ◽  
T. Kimura ◽  
J. Nishizawa
Keyword(s):  
Raman Laser ◽  
Pump Light

Non-Plasmonic SERS with Silicon: Is It Really Safe? New Insights into Opto-Thermics of Core/Shell Microbeads

2018 ◽  
Author(s):  
Nicolò Bontempi ◽  
Irene Vassalini ◽  
Stefano Danesi ◽  
Matteo Ferroni ◽  
Paolo Colombi ◽  
...  
Keyword(s):  
Critical Role ◽  
Raman Laser ◽  
Core Shell ◽  
Thermal Coupling ◽  
Melting Points ◽  
Experimental Proof ◽  
Weakly Coupled ◽  
Light Management ◽  
Laser Sources ◽  
First Time

<p>Here we investigate for the first time the opto-thermal behavior of SiO<sub>2</sub>/Si core/shell microbeads (Si-rex) irradiated with three common Raman laser sources (lambda=532, 633, 785 nm) under real working conditions. We obtained an experimental proof of the critical role played by bead size and aggregation in heat and light management, demonstrating that in the case of strong opto-thermal coupling the temperature can exceed that of the melting points of both core and shell components. In addition, we also show that weakly coupled beads can be utilized as stable substrates for plasmon-free SERS experiments.</p>

Dynamical Nuclear Polarization

2018 ◽  
Author(s):  
M. M. Glazov
Keyword(s):  
Spin Polarization ◽  
Nuclear Spin ◽  
Nuclear Polarization ◽  
Magnetic Moments ◽  
Nonlinear Effects ◽  
Many Body ◽  
Nuclear Spin Polarization ◽  
Optical Resonances ◽  
Dynamical Nuclear Polarization ◽  
Temperature Concept

The transfer of nonequilibrium spin polarization between the electron and nuclear subsystems is studied in detail. Usually, a thermal orientation of nuclei in magnetic field is negligible due to their small magnetic moments, but if electron spins are optically oriented, efficient nuclear spin polarization can occur. The microscopic approach to the dynamical nuclear polarization effect based on the kinetic equation method, along with a phenomenological but very powerful description of dynamical nuclear polarization in terms of the nuclear spin temperature concept is given. In this way, one can account for the interaction between neighbouring nuclei without solving a complex many-body problem. The hyperfine interaction also induces the feedback of polarized nuclei on the electron spin system giving rise to a number of nonlinear effects: bistability of nuclear spin polarization and anomalous Hanle effect, dragging and locking of optical resonances in quantum dots. Theory is illustrated by experimental data on dynamical nuclear polarization.

scholarly journals Multifunctional Optical Crystals for All-Solid-State Raman Lasers

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 114
Author(s):  
Hui Zhao ◽  
Shibo Dai ◽  
Siqi Zhu ◽  
Hao Yin ◽  
Zhen Li ◽  
...  
Keyword(s):  
Solid State ◽  
Continuous Wave ◽  
Frequency Doubling ◽  
Raman Laser ◽  
Rare Earth Ions ◽  
Excellent Performance ◽  
The Past ◽  
Raman Lasers ◽  
Optical Crystals ◽  
Laser Crystals

In the past few decades, the multifunctional optical crystals for all-solid-state Raman lasers have been widely studied by many scholars due to their compactness, convenience and excellent performance. In this review, we briefly show two kinds of multifunctional Raman crystals: self-Raman (laser and Raman effects) crystals and self-frequency-doubled Raman (frequency-doubling and Raman effects) crystals. We firstly introduce the properties of the self-Raman laser crystals, including vanadate, tungstate, molybdate and silicate doped with rare earth ions, as well as self-frequency-doubled Raman crystals, including KTiOAsO4 (KTA) and BaTeMo2O9 (BTM). Additionally, the domestic and international progress in research on multifunctional Raman crystals is summarized in the continuous wave, passively Q-switched, actively Q-switched and mode-locked regimes. Finally, we present the bottleneck in multifunctional Raman crystals and the outlook for future development. Through this review, we contribute to a general understanding of multifunctional Raman crystals.

Erosion Experiment of Self-Excited Oscillation Pulsed Jet

2014 ◽  
Vol 937 ◽  
pp. 614-619
Author(s):  
Chuan Lin Tang ◽  
Jie Pei ◽  
Dong Hu ◽  
Xiao Ting He
Keyword(s):  
Significant Influence ◽  
Cavity Length ◽  
Experimental Studies ◽  
The Self ◽  
Erosion Depth ◽  
Pulsed Jet ◽  
Excited Oscillation ◽  
Erosion Effect ◽  
Erosion Volume ◽  
Peak Value

In order to improve the erosion effect of jet under submergence condition, experimental studies of erosion generated from the self-excited pulsed jet was carried out by using developed self-excited oscillation nozzle. The erosion volume and depth of pulsed jet were measured and taking mortar block as an erosion part. The results were that the standoff has significant influence on erosion effect. The erosion volume firstly decreases with increases in cavity length and then increases to a peak value. Erosion volume of pulsed jet is significantly higher than that of continuous jet, the erosion depth of two jet has slight difference.

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