Papers by Sergei Smetanin
Crystals
The effect of the self-separation of a single ultrashort light pulse of a parametric Raman CaMoO4... more The effect of the self-separation of a single ultrashort light pulse of a parametric Raman CaMoO4 laser with birefringence phase matching under intracavity synchronous pumping by a mode-locked 1064 nm Nd:YAG laser is experimentally investigated and theoretically simulated. The conditions for the self-separation effect for the single ultrashort pulse at an anti-Stokes wavelength of 973 nm with the pulse duration of 9 ps and the pulse energy of up to 9 μJ are defined.
Photonics, Devices, and Systems VII
A novel, all-solid-state, self-mode-locked, collinearly phase-matched, parametric Raman Nd:YAG/Ca... more A novel, all-solid-state, self-mode-locked, collinearly phase-matched, parametric Raman Nd:YAG/CaCO3 laser at 1168 nm anti-Stokes wavelength is reported. We have achieved parametric Raman conversion into the 1565 nm Stokes and 1168 nm anti-Stokes components and self-mode-locking using single Kerr-lens and Raman-active CaCO3 nonlinear crystal inside the cavity of the diode side-pumped Nd:YAG laser generating at 1338 nm. Collinear phase matching of equally polarized Stokes-anti-Stokes coupling was self-organized due to zero dispersion of the CaCO3 crystal at the fundamental laser wavelength of 1338 nm. We demonstrate possibilities of the Stokes and anti-Stokes picosecond pulse shortening and separation of few and even only one 120 ps ultra-short 1168 nm anti-Stokes pulse from the self-modelocked laser pulse train because of fast and spatially uniform depletion of pumping of intracavity Raman conversion without using any electro-optical device. We have obtained high energy output of up to 1.1 μJ in the single intensive anti-Stokes 120 ps ultra-short pulse which was up to 6.8 % from overall output radiation pulse train energy.
2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)
At present, we can observe progress in physics of crystalline Raman lasers leading to efficient n... more At present, we can observe progress in physics of crystalline Raman lasers leading to efficient nonlinear frequency conversion at transient regime for generation of ultra-short pulses of stimulated Raman scattering (SRS) radiation with picosecond duration and shorter [1,2]. Recently the problem of a femtosecond crystalline Raman laser with femtosecond pumping has been solved [1] using an efficient SRS in a Raman-active crystal (CVD-diamond) under synchronous pumping by repetitive femtosecond laser pulses in an external cavity with a round-trip time equal to the pump pulse repetition period. However, a challenge of femtosecond SRS pulse generation in crystals under pumping by picosecond lasers which is more simple, inexpensive, and prevalent in comparison with the unique femtosecond laser systems remained unsolved.
Laser Congress 2017 (ASSL, LAC), 2017
Nonlinear Optics and Applications XI, 2019
New possibilities to use the zircon-type YVO4 and GdVO4 Raman-active crystals for extreme SRS-rad... more New possibilities to use the zircon-type YVO4 and GdVO4 Raman-active crystals for extreme SRS-radiation pulse shortening higher than 30 times down to the inverse value of the vibrational Raman line width in a synchronouslypumped crystalline Raman laser with combined long (ν1) and short (ν2) shift Raman conversion have been found. It is caused by strong broadening of the short-shift bending vibration ν2 line in the spontaneous Raman spectrum of these crystals. We report characteristics of all-solid-state extracavity Raman lasers based on the 16-mm long a-cut YVO4 (ν1 = 889 cm–1, ν2 = 376 cm–1) and GdVO4 (ν1 = 882 cm–1, ν2 = 382 cm–1) crystals under synchronous pumping by a 1063-nm 35-picosecond Nd:GdVO4 laser. Lasing was obtained in the YVO4 (GdVO4) Raman laser at not only the ν1- shifted first Stokes wavelength of 1173 nm (1174 nm), but also at the (ν1 + ν2)-shifted Stokes wavelength of 1228 nm (1228 nm) with slope efficiency of 5.8 % (5.0 %) and output pulse energy up to 11 nJ (10 nJ) at 1228 nm. At 50 μm positive detuning of the external cavity length the strongest 30-fold and 42-fold shortening of the (ν1+ν2)-shifted Raman radiation pulse down to 1.2 ps and 850 fs in the YVO4 and GdVO4 crystals, respectively, has been achieved. These values are close to the inverse values of the ν2 line widths of 11 cm–1 and 24 cm–1, respectively.
Solid State Lasers XXX: Technology and Devices, 2021
Application of new nonlinear-optical crystals for development of novel methods for nonlinear-opti... more Application of new nonlinear-optical crystals for development of novel methods for nonlinear-optical conversion of solid-state laser radiation into mid-infrared range presents an important task of modern infrared photonics. Significance of this challenge is caused not only by limited choice of solid-state sources of coherent radiation in mid-infrared range, but also by potential applications of such sources in science, technology, medicine, and biology. Efficient method of optical frequency down-conversion is the difference-frequency generation (DFG) allowing the single-pass conversion of the pump and signal optical frequencies lying in the near-IR range into the mid-IR idler wave. The narrowband, frequency stable signal wave for the DFG is generated in our setup by the stimulated Raman scattering (SRS) in a cubically nonlinear crystal (CaCO3, BaWO4, or diamond). In order to present a comparative study, the LiGaSe2 and LiGaS2 crystals with the equal length of 8 mm were used. Narrowband idler waves at the discrete wavelengths of 4.6 / 5.4 / 7.5 / 9.2 μm and high pulse energies in the range 10 - 50 μJ were generated. The measured linewidths were close to the monochromator resolution limit of < 2 cm-1 (~10 nm @ 7.5 μm) and they can be even narrower. It can be supposed that the idler wave linewidth should be comparable with the Raman mode linewidth (ΔνR = 1.2 2.7 cm-1). Generation at 10.8 μJ was achieved in LiGaSe2 only and the output energy was at in the order of ~100 μJ (close to the measuring probe resolution limit).
A lot of attention is currently focused on synchronously pumped, extra-cavity crystalline Raman l... more A lot of attention is currently focused on synchronously pumped, extra-cavity crystalline Raman lasers generating one or two Stokes Raman components in KGW or diamond Raman-active crystals, and also generating additional components of stimulated polariton scattering in lithium niobate crystal having both cubic and quadratic nonlinearities. In this contribution we report on generation of more than two Stokes components of stimulated Raman scattering with different Raman shifts in the all-solid-state, synchronously pumped, extra-cavity Raman laser based on the Raman-active a-cut BaWO4 crystal excited by a mode-locked, 220 nJ, 36 ps, 150 MHz diode sidepumped Nd:GdVO4 laser generating at the wavelength of 1063 nm. Excitation by the pumping radiation polarized along the BaWO4 crystal optical axis resulted in the Raman generation with not only usual (925cm – 1), but also additional (332cm – 1) Raman shift. Besides the 1180-nm first and 1323 nm second Stokes components with the Raman shift...
Laser Congress 2017 (ASSL, LAC), 2017
Self-organized separation of a few and even only one ultra-short 120-ps 1168-nm anti-Stokes pulse... more Self-organized separation of a few and even only one ultra-short 120-ps 1168-nm anti-Stokes pulse from the pulse train generated by all-solid-state, self-mode-locked, parametric Raman Nd:YAG/CaCO3 laser without using any electro-optical device is proposed and demonstrated.
Parametric four-wave mixing of frequency components in a crystalline Raman laser allowed generati... more Parametric four-wave mixing of frequency components in a crystalline Raman laser allowed generation of a collimated beam of not only Stokes, but also anti-Stokes components of the Raman radiation. Recently, to widen the angular tolerance of four-wave mixing and to obtain high conversion efficiency into the anti-Stokes wave, we have developed new schemes of the parametric Raman anti-Stokes lasers at 503 nm and 954 nm with tangentially phase-matched collinear beam interaction of orthogonally-polarized Raman components in a CaCO3 crystal under 532 nm and 1064 nm laser pumping. Now we use not only the CaCO3 crystal, but also other Raman-active crystals with different birefringence for the tangentially phase-matched parametric Raman laser under green (532 nm) pumping. We have theoretically and experimentally studied characteristics of tangential phase matching of Stokes <–< anti-Stokes interaction for different negative and positive uniaxial crystals with high and low birefringence...
2021 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC), 2021
Multiwavelength, near-IR (1000-1400 nm), high-repetition-rate, ultrashort laser pulses converted ... more Multiwavelength, near-IR (1000-1400 nm), high-repetition-rate, ultrashort laser pulses converted by cascaded stimulated Raman scattering (SRS) have many potential applications connected with multiphoton interactions of coherent radiation with matter. Utilization of mixed Raman-active crystals can make it possible not only to enrich the generated SRS radiation spectra, but also to improve other the radiation characteristics, in particular, to ensure shortening of the laser pulses. One of the candidates is a Pb(MoO 4 ) x (WO 4 ) 1 – x mixed crystal having two-mode behaviour (corresponding to the molybdate and tungstate anionic groups) for the high-frequency (ν 1 ) stretching vibrations of the anionic groups, but one-mode behaviour for the low-frequency (ν 2 ) bending vibrations of the anionic groups [1] as it shows Fig. 1 (a) for Pb(MoO 4 ) 0.5 (WO 4 ) 0.5 . Single-pass picosecond SRS in Pb(MoO 4 ) 0.5 (WO 4 ) 0.5 has been earlier realized and shown laser frequency conversion only on the two-mode ν 1 (MoO 4 ) and ν 1 (WO 4 ) stretching vibrations [2] . In the present work we demonstrate the synchronously pumped Pb(MoO 4 ) 0.5 (WO 4 ) 0.5 Raman laser operation with combined frequency shifts not only on the two-mode stretching (ν 1 ) Raman frequencies, but also on the one-mode bending ν 2 (MoO 4 + WO 4 ) broadened (Δν 2 = 10 cm –1 ) Raman line, allowing to shorten the (ν 1 + ν 2 )-shifted SRS pulses down to 1/(π c Δν ) ≈ 2 1 ps.
Optics Letters, 2021
In this Letter, a mixed P b ( M o O 4 ) 0.2 ( W O 4 ) 0.8 as a new, to the best of our knowledge,... more In this Letter, a mixed P b ( M o O 4 ) 0.2 ( W O 4 ) 0.8 as a new, to the best of our knowledge, active medium with optimized content for a synchronously pumped multiwavelength Raman laser with a combined frequency shift is presented. The unique structure of this crystal resulted in oscillations at 12 closely spaced output wavelengths in a spectral range from 1128 to 1360 nm. The strongest pulse shortening in comparison with nominally pure scheelite-like crystals has been achieved.
Optics Express, 2020
For the first time to our knowledge, the operation of a synchronously pumped ultrafast Raman lase... more For the first time to our knowledge, the operation of a synchronously pumped ultrafast Raman laser that uses a PbMoO4 crystal as the active medium has been demonstrated. We achieved efficient Raman conversion in PbMoO4 from pumping 1063 nm into 1171 and 1217 nm, respectively, at single and combined frequency shifts on stretching and bending Raman modes. The output pulse energy (up to 160 nJ) and peak power (up to 11 kW) of the output picosecond radiation is the highest among all-solid-state synchronously pumped Raman lasers published to date. The strongest pulse shortening at 1217 nm down to 1.4 ps was obtained that is close to the bending mode dephasing time.
Optics Express, 2020
Collinear phase matching of the Stokes ↔ anti-Stokes interaction for Raman-active crystals with d... more Collinear phase matching of the Stokes ↔ anti-Stokes interaction for Raman-active crystals with different birefringence was studied theoretically as well as experimentally. It was shown that collinear phase matching of the Stokes ↔ anti-Stokes interaction in low-birefringent crystals can be insensitive to angular mismatch if a phase matching angle is higher than 60°. We have developed and experimentally realized an extracavity parametric Raman anti-Stokes laser based on a low-birefringent SrWO4. Cyan 507-nm anti-Stokes conversion from green (532 nm) pump radiation of a 5-ns, 1-mJ second harmonic Nd:YAG laser has been obtained. Laser setup with a single beam excitation made it possible to use an output face of the SrWO4 crystal as an output coupler because of wide (6°) angular tolerance of collinear phase matching that resulted in an increase of slope efficiency of anti-Stokes generation higher than 3% at the anti-Stokes energy output of a 10-µJ level.
Crystals, 2019
Comparative investigation of characteristics of spontaneous and stimulated Raman scattering (SRS)... more Comparative investigation of characteristics of spontaneous and stimulated Raman scattering (SRS) in different alkali-earth tungstate and molybdate crystals at both high and low frequency anionic group vibrations is presented. It has been found that, among these crystals, the SrMoO4 and SrWO4 crystals are the most perspective for SRS generation on both stretching and bending modes of internal anionic group vibrations with the strongest SRS pulse shortening under synchronous laser pumping because of not only highly intense stretching mode Raman line for efficient primary extra cavity long-shifted SRS conversion but also the widest bending mode Raman line for the strongest SRS pulse shortening down to the inverse width of the widest Raman line (~1 ps) at secondary intracavity short-shifted SRS conversion. The strongest 26-fold pump pulse shortening down to 1.4 ps at the Stokes component with the combined Raman shift in the synchronously pumped extra cavity SrMoO4 and SrWO4 Raman laser...
SPIE Proceedings, 2017
Lasers based on stimulated-Raman-scattering process can be used for the frequency-conversion to t... more Lasers based on stimulated-Raman-scattering process can be used for the frequency-conversion to the wavelengths that are not readily available from solid-state lasers. Parametric Raman lasers allow generation of not only Stokes, but also anti-Stokes components. However, practically all the known crystalline parametric Raman anti-Stokes lasers have very low conversion efficiencies of about 1 % at theoretically predicted values of up to 40 % because of relatively narrow angular tolerance of phase matching in comparison with angular divergence of the interacting beams. In our investigation, to widen the angular tolerance of four-wave mixing and to obtain high conversion efficiency into the antiStokes wave we propose and study a new scheme of the parametric Raman anti-Stokes laser at 503 nm with phasematched collinear beam interaction of orthogonally polarized Raman components in calcite under 532 nm 20 ps laser pumping. We use only one 532-nm laser source to pump the Raman-active calcite crystal oriented at the phase matched angle for orthogonally polarized Raman components four-wave mixing. Additionally, we split the 532-nm laser radiation into the orthogonally polarized components entering to the Raman-active calcite crystal at the certain incidence angles to fulfill the tangential phase matching compensating walk-off of extraordinary waves for collinear beam interaction in the crystal with the widest angular tolerance of four-wave mixing. For the first time the highest 503-nm anti-Stokes conversion efficiency of 30 % close to the theoretical limit of about 40 % at overall optical efficiency of the parametric Raman anti-Stokes generation of up to 3.5 % in calcite is obtained due to realization of tangential phase matching insensitive to the angular mismatch.
Laser Physics, 2003
SRS transformation of the trains of pulses of a self-pumped phase-conjugate Nd:YAG laser is studi... more SRS transformation of the trains of pulses of a self-pumped phase-conjugate Nd:YAG laser is studied using a Ba(NO 3 ) 2 crystal. It is demonstrated that the mean power of the first Stokes component of the SRS radiation can be as high as 5 W at pulse energy, greater than 30 mJ and a transformation efficiency of 15-30%.
CLEO: 2015, 2015
The optimal conditions of low-threshold collinear parametric Raman-comb generation in calcite fro... more The optimal conditions of low-threshold collinear parametric Raman-comb generation in calcite from the 477-nm second anti-Stokes to 692-nm fourth Stokes component under 20-ps laser excitation at 532-nm are demonstrated in good agreement with theoretical model.
SPIE Proceedings, 1999
The repetitively pulsed Nd:YAG laser with dynamic cavity formed with participation of dynamic hol... more The repetitively pulsed Nd:YAG laser with dynamic cavity formed with participation of dynamic holographic gratings induced in Nd:YAG laser crystal and Li:F absorber has been investigated. The generation regimes and technological opportunities of this Nd:YAG laser were studied. High spatial brightness of radiation at diffraction limited divergence has allowed to carry out effective punching of calibrate holes in different materials with a diameter up to 15 micrometers and maximal depth up to 20 mm.
2014 International Conference Laser Optics, 2014
Solid-state blue-laser generation by nonlinear frequency conversion of the 1.338-µm Nd:YAG laser ... more Solid-state blue-laser generation by nonlinear frequency conversion of the 1.338-µm Nd:YAG laser MOPA system is experimentally investigated. The 0.446-µm blue radiation is obtained by frequency-tripling technique as the frequency doubling (0.669 μm) with the sum-frequency oscillation (1.338 μm + 0.669 μm). The blue laser pulse output energy of 2 mJ with 20-ns duration and 2-% conversion efficiency is achieved allowing for laser power scaling.
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Papers by Sergei Smetanin