Nonlinear refractive properties of chloroaluminum phthalocyanine （CAP） in ethanol solution are studied using the Z-scan technique with picosecond （ps） and nanosecond （ns） laser pulses at a wavelength of 532nm. A...Nonlinear refractive properties of chloroaluminum phthalocyanine （CAP） in ethanol solution are studied using the Z-scan technique with picosecond （ps） and nanosecond （ns） laser pulses at a wavelength of 532nm. A transition from self-focusing to self-defocusing in CAP solution excited by 10 ns pulses is observed during the decrease of its concentration.This transition is due to co-existing excited-state refraction and transient thermal lensing effects.The experimental results are described very well using the rate-equation model and the theory of transient thermal refraction in liquids.The refractive cross sections of the excited-state are also obtained.展开更多
Coherent rainbows can be formed by focusing white-light laser into liquids.They are bilaterally symmetric interference rings with various shapes.Such interference rings arise from the temperature distribution of the l...Coherent rainbows can be formed by focusing white-light laser into liquids.They are bilaterally symmetric interference rings with various shapes.Such interference rings arise from the temperature distribution of the liquid induced by laser heating,i.e.,thermal lens effect,which changes the refractive index locally and thus the optical path difference.The up-down asymmetry of the interference rings is caused by convection in the liquid.With the increase of the viscosity,the interference rings change their shape from oval to circular shape.After a shutter is opened and the laser shines into the liquid,the interference rings are circular at the beginning.As time goes on,they gradually turn into an oval shape.Let the liquid go a free-fall at the beginning,the interference rings remain circular.All the three experiments have confirmed that the asymmetric interference rings are due to convection in the liquid associated with thermal lens effect.We also numerically simulate the two-dimensional heat conduction with and without convection,whose results agree well with our experimental observations.展开更多
This study develops a Yb:KGW dual-crystal based regenerative amplifier.The thermal lensing and gain-narrowing effects are compensated by the dual-crystal configuration.Sub-nanojoule pulses are amplified to 1.5 mJ with...This study develops a Yb:KGW dual-crystal based regenerative amplifier.The thermal lensing and gain-narrowing effects are compensated by the dual-crystal configuration.Sub-nanojoule pulses are amplified to 1.5 mJ with 9 nm spectral bandwidth and 1 kHz repetition rate using chirped pulse amplification technology.Consequently,1.2 m J pulses with a pulse duration of 227 fs are obtained after compression.Thanks to the cavity design,the output laser was a near diffraction limited beam with M2 around 1.1.The amplifier has the potential to boost energy above 2 m J after compression and act as a front end for a future kilohertz terawatt-class diode-pumped Yb:KGW laser system.展开更多
A simple,compact,double-pass pumped Nd:YVO4 thin disk laser is demonstrated.Its continuous-wave performance with different Nd doping concentrations and thicknesses is investigated experimentally.The maximum output pow...A simple,compact,double-pass pumped Nd:YVO4 thin disk laser is demonstrated.Its continuous-wave performance with different Nd doping concentrations and thicknesses is investigated experimentally.The maximum output power of 17.7 W is achieved by employing a 0.5 at.%doped sample,corresponding to an optical-to-optical efficiency of 46% with respect to the absorbed pump power.In addition,a numerical analysis and an experimental study of the temperature distribution,and thermal lens effect of the Nd:YVO4 thin disk,are presented considering the influence of the energy transfer upconversion effect and the temperature dependence of the thermal conductivity tensor.The simulated results are in good agreement with the experimental results.展开更多
基金Project supported by the National Natural Science Fundation of China (Grant No 10104007)the Program for New Century Excellent Talents in University,China (Grant No NCET-04-0333)the Excellent Youth Fund of Heilongjiang Province,China(Grant No JC-04-04)
文摘Nonlinear refractive properties of chloroaluminum phthalocyanine （CAP） in ethanol solution are studied using the Z-scan technique with picosecond （ps） and nanosecond （ns） laser pulses at a wavelength of 532nm. A transition from self-focusing to self-defocusing in CAP solution excited by 10 ns pulses is observed during the decrease of its concentration.This transition is due to co-existing excited-state refraction and transient thermal lensing effects.The experimental results are described very well using the rate-equation model and the theory of transient thermal refraction in liquids.The refractive cross sections of the excited-state are also obtained.
基金Project supported by the National Key Research and Development Program of China(Grant No.2016YFA0301202)the National Natural Science Foundation of China(Grant Nos.11674311 and U20A20205)。
文摘Coherent rainbows can be formed by focusing white-light laser into liquids.They are bilaterally symmetric interference rings with various shapes.Such interference rings arise from the temperature distribution of the liquid induced by laser heating,i.e.,thermal lens effect,which changes the refractive index locally and thus the optical path difference.The up-down asymmetry of the interference rings is caused by convection in the liquid.With the increase of the viscosity,the interference rings change their shape from oval to circular shape.After a shutter is opened and the laser shines into the liquid,the interference rings are circular at the beginning.As time goes on,they gradually turn into an oval shape.Let the liquid go a free-fall at the beginning,the interference rings remain circular.All the three experiments have confirmed that the asymmetric interference rings are due to convection in the liquid associated with thermal lens effect.We also numerically simulate the two-dimensional heat conduction with and without convection,whose results agree well with our experimental observations.
基金supported by the Natural Science Foundation of Top Talent of SZTU(Nos.2019010801001 and 202024555101039)。
文摘This study develops a Yb:KGW dual-crystal based regenerative amplifier.The thermal lensing and gain-narrowing effects are compensated by the dual-crystal configuration.Sub-nanojoule pulses are amplified to 1.5 mJ with 9 nm spectral bandwidth and 1 kHz repetition rate using chirped pulse amplification technology.Consequently,1.2 m J pulses with a pulse duration of 227 fs are obtained after compression.Thanks to the cavity design,the output laser was a near diffraction limited beam with M2 around 1.1.The amplifier has the potential to boost energy above 2 m J after compression and act as a front end for a future kilohertz terawatt-class diode-pumped Yb:KGW laser system.
基金Ministry of Science and Technology of the People's Republic of China(MOST)(2016YFB1102402,2017YFB0405202)Key Laboratory of Opto-electronic Information Technology,Ministry of Education(Tianjin University),China(2019KFKT003)Shanghai Science and Technology Achievements Transformation and Industrialization project(18511109800).
文摘A simple,compact,double-pass pumped Nd:YVO4 thin disk laser is demonstrated.Its continuous-wave performance with different Nd doping concentrations and thicknesses is investigated experimentally.The maximum output power of 17.7 W is achieved by employing a 0.5 at.%doped sample,corresponding to an optical-to-optical efficiency of 46% with respect to the absorbed pump power.In addition,a numerical analysis and an experimental study of the temperature distribution,and thermal lens effect of the Nd:YVO4 thin disk,are presented considering the influence of the energy transfer upconversion effect and the temperature dependence of the thermal conductivity tensor.The simulated results are in good agreement with the experimental results.
