scholarly journals Discretely Tunable Multiwavelength Visible Laser Based on Cascaded Frequency Conversion Processes

2020 ◽  
Vol 10 (23) ◽  
pp. 8608
Author(s):  
Xinlin Lv ◽  
Junchi Chen ◽  
Yujie Peng ◽  
Zhiyuan Huang ◽  
Yingbin Long ◽  
...  
Keyword(s):  
Conversion Efficiency ◽  
Frequency Conversion ◽  
Second Harmonic ◽  
Raman Laser ◽  
Maximum Energy ◽  
Laser Oscillator ◽  
Sum Frequency ◽  
Wide Range ◽  
Visible Laser ◽  
Visible Wavelengths

We demonstrate a discretely tunable multiwavelength visible laser through second harmonic generation (SHG) and sum frequency generation (SFG) of multiorder Stokes lasers generated from an external Raman laser oscillator. The Raman laser oscillator, driven by a 1064 nm laser with an energy of 120 mJ, is based on a cascade of Ba(NO3)2 and two axial orthogonal KGd(WO4)2 crystals. Through adjusting the angle of the SHG/SFG crystal, we obtain 16 visible wavelengths with a wide range from 579.5–658.4 nm. In addition, we investigate the output energy and conversion efficiency of the resulting laser with various phase-matching angles. We show that the maximum energy of the visible laser is 8.87 mJ with five wavelengths, and the corresponding total conversion efficiency is 7.4%. These experimental results demonstrate a practical and effective method of generating a discretely tunable multiwavelength visible laser.

scholarly journals Simultaneous Second-Harmonic, Sum-Frequency Generation and Stimulated Raman Scattering in MgO:PPLN

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2266
Author(s):  
Dismas Choge ◽  
Huaixi Chen ◽  
Lei Guo ◽  
Guangwei Li ◽  
Wanguo Liang
Keyword(s):  
Raman Scattering ◽  
Stimulated Raman Scattering ◽  
Second Harmonic ◽  
Sum Frequency Generation ◽  
Laser Source ◽  
Sum Frequency ◽  
Wide Range ◽  
Multi Wavelength ◽  
Frequency Generation ◽  
Stimulated Raman

In this study, simultaneous second-harmonic generation (SHG), sum frequency generation (SFG), and Raman conversion based on MgO-doped periodically poled lithium niobate (MgO:PPLN) for multi-wavelength generation is demonstrated. The approach used is based on a single MgO:PPLN crystal poled with a uniform period of 10.2 µm that phase matches SHG and SFG, simultaneously. Using a simplified double-pass geometry, up to 0.8 W of blue light at 487 nm is achieved by a frequency-doubling 974 nm laser diode pump, and 0.5 W of orange light at 598 nm is generated by frequency mixing 974 nm pump with C-band (1527–1565 nm) tunable laser source. At high pump powers of the 974 nm laser source, other unexpected peaks at 437, 536, 756, 815 and 1038 nm were observed, of which the 1038 nm line is due to Stimulated Raman Scattering within the MgO:PPLN crystal. The resulting multi-wavelength light source may find a wide range of applications in biomedicine and basic research.

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 Optical anapole mode in nanostructured lithium niobate for enhancing second harmonic generation

Nanophotonics ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 3575-3585 ◽  
Author(s):  
Yang Li ◽  
Zhijin Huang ◽  
Zhan Sui ◽  
Huajiang Chen ◽  
Xinyue Zhang ◽  
...  
Keyword(s):  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Conversion Efficiency ◽  
Second Harmonic ◽  
Nonlinear Coefficient ◽  
Excitation Wavelength ◽  
Pump Light ◽  
Hyperbolic Metamaterials ◽  
Wide Range ◽  
Nonlinear Conversion

AbstractSecond harmonic generation (SHG) with a material of large transparency is an attractive way of generating coherent light sources at exotic wavelength range such as VUV, UV and visible light. It is of critical importance to improve nonlinear conversion efficiency in order to find practical applications in quantum light source and high resolution nonlinear microscopy, etc. Here an enhanced SHG with conversion efficiency up to 10−2% at SH wavelength of 282.7 nm under 11 GW/cm2 pump intensity via the excitation of anapole in lithium niobite (LiNbO3, or LN) nanodisk through the dominating d33 nonlinear coefficient is investigated. The anapole has advantages of strongly suppressing far-field scattering and well-confined internal field which helps to boost the nonlinear conversion. Anapoles in LN nanodisk is facilitated by high index contrast between LN and substrate with properties of near-zero-index via hyperbolic metamaterial structure design. By tailoring the multi-layers structure of hyperbolic metamaterials, the anapole excitation wavelength can be tuned at different wavelengths. It indicates that an enhanced SHG can be achieved at a wide range of pump light wavelengths via different design of the epsilon-near-zero (ENZ) hyperbolic metamaterials substrates. The proposed nanostructure in this work might hold significances for the enhanced light–matter interactions at the nanoscale such as integrated optics.

scholarly journals Direct visualization of phase-matched efficient second harmonic and broadband sum frequency generation in hybrid plasmonic nanostructures

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Zhe Li ◽  
Brian Corbett ◽  
Agnieszka Gocalinska ◽  
Emanuele Pelucchi ◽  
Wen Chen ◽  
...  
Keyword(s):  
Conversion Efficiency ◽  
Second Harmonic ◽  
Effective Means ◽  
Sum Frequency Generation ◽  
Mode Analysis ◽  
Plasmonic Nanostructures ◽  
Integrated Photonics ◽  
Direct Visualization ◽  
Sum Frequency ◽  
Frequency Generation

Abstract Second harmonic generation and sum frequency generation (SHG and SFG) provide effective means to realize coherent light at desired frequencies when lasing is not easily achievable. They have found applications from sensing to quantum optics and are of particular interest for integrated photonics at communication wavelengths. Decreasing the footprints of nonlinear components while maintaining their high up-conversion efficiency remains a challenge in the miniaturization of integrated photonics. Here we explore lithographically defined AlGaInP nano(micro)structures/Al2O3/Ag as a versatile platform to achieve efficient SHG/SFG in both waveguide and resonant cavity configurations in both narrow- and broadband infrared (IR) wavelength regimes (1300–1600 nm). The effective excitation of highly confined hybrid plasmonic modes at fundamental wavelengths allows efficient SHG/SFG to be achieved in a waveguide of a cross-section of 113 nm × 250 nm, with a mode area on the deep subwavelength scale (λ2/135) at fundamental wavelengths. Remarkably, we demonstrate direct visualization of SHG/SFG phase-matching evolution in the waveguides. This together with mode analysis highlights the origin of the improved SHG/SFG efficiency. We also demonstrate strongly enhanced SFG with a broadband IR source by exploiting multiple coherent SFG processes on 1 µm diameter AlGaInP disks/Al2O3/Ag with a conversion efficiency of 14.8% MW−1 which is five times the SHG value using the narrowband IR source. In both configurations, the hybrid plasmonic structures exhibit >1000 enhancement in the nonlinear conversion efficiency compared to their photonic counterparts. Our results manifest the potential of developing such nanoscale hybrid plasmonic devices for state-of-the-art on-chip nonlinear optics applications.

Deterioration of the Frequency-Conversion Efficiency of aLiTaO3Waveguide Device with Nonlinear Quasi-Phase-Matched Second-Harmonic Generation

1996 ◽  
Vol 35 (Part 1, No. 7) ◽  
pp. 3902-3903
Author(s):  
Yukihiro Yamamoto ◽  
Satoshi Yamaguchi ◽  
Noriko Yamada ◽  
Takahiro Matsumoto ◽  
Yukiko Kondo
Keyword(s):  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Conversion Efficiency ◽  
Frequency Conversion ◽  
Second Harmonic
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