The pump-probe Raman-induced optical Kerr effect (RIKE) of simple molecular liquids, studied with... more The pump-probe Raman-induced optical Kerr effect (RIKE) of simple molecular liquids, studied with femtosecond laser pulses, exhibit long lasting beats ascribable to vibrational quantum interference (QI). While energy conservation entails vibrational resonances in RIKE, momentum conservation boils down to wave vector-matching in the pump and probe processes, which calls for the participation of a vibrational excitation wave. The refractive index
2009 Conference on Lasers & Electro Optics & The Pacific Rim Conference on Lasers and Electro-Optics, 2009
1, Shuefu Rd., Nei-pu, Ping-tung 912, Taiwan, China .3Department of Construction Engineering, Nat... more 1, Shuefu Rd., Nei-pu, Ping-tung 912, Taiwan, China .3Department of Construction Engineering, National Yunlin University of Science and Technology, 123 University Rd., Section 3,Dou-liou, Yun-lin 640, Taiwan, China 1Email: phyjlt@.ccu.edu.tw; 3Email: wangjn@ ...
2009 Conference on Lasers & Electro Optics & The Pacific Rim Conference on Lasers and Electro-Optics, 2009
We present recent studies of negative lensing effect observed in several molecular liquids using ... more We present recent studies of negative lensing effect observed in several molecular liquids using Z-scan technique and 28 femtosecond 800 nm laser pulses. Raman induced Kerr effect and thermal lensing effect are invoked to explain the sign of nonlinear refraction.
2009 Conference on Lasers & Electro Optics & The Pacific Rim Conference on Lasers and Electro-Optics, 2009
Page 1. Nonlinear Absorption of InN Epitaxial Films Probed by Femtosecond Pulsed Transmission Z-s... more Page 1. Nonlinear Absorption of InN Epitaxial Films Probed by Femtosecond Pulsed Transmission Z-scan Measurements Tsong-Ru Tsai1, Tsung-Han Wu1, Jung-Cheng Liao1, Tai-Huei Wei2, Hai-Pang Chiang1, Jih-Shang Hwang1, Din-Ping Tsai3, and Yang-Fang Chen3 ...
Use was made of a novel Fabry–Pe´rot interferometer technique to determine the variation of refra... more Use was made of a novel Fabry–Pe´rot interferometer technique to determine the variation of refractive index with temperature (∂n/∂T) of a potassium niobate crystal with a GaAlAs diode laser. The transverse intensity distributions of the laser transmitted through the crystal were found to be temperature dependent, and the ∂n/∂T values along crystallographic b and c axes were determined to be −4.5×10−5 and 6.1×10−5 °C−1, respectively. The temperature changes required for tangential tuning from transverse mode TEMqmn to TEMqm+1n and sagittal tuning from TEMqmn to TEMqmn+1 were found to be 0.29 and 1.27 °C, respectively, when the laser was polarized along the b axis. When the laser polarization was along the c axis, the tangential and sagittal tunings were found to be 0.10 and 0.54 °C, respectively. These differences between the tangential and sagittal directions indicated that the monolithic ring resonator used was indeed asymmetric.
The principles of operation of semiconductor optical limiters which utilize two-photon absorption... more The principles of operation of semiconductor optical limiters which utilize two-photon absorption and free-carrier induced defocusing are described. We present a review of early work using psec pulses at 532 nm in ZnSe, in which the problem of damage in solid state limiters is overcome by optimizing the focusing geometry. Limiting energies as loW as 10 nJ are seen, and a dynamic range (damage energy divided by limiting energy) in excess of 104 is demonstrated. The somewhat complicated propagation theory is simplified into a set of scaling rules which are used to predict operating characteristics of semiconductor limiters at longer wavelengths and for shorter pulses. We present new limiting data obtained with longer pulses in ZnSe, in CdTe at 1.06 mum and InSb at 10.6 mum, and we compare these results with the scaling rules.
Using the Z-scan technique, we studied the nonlinear absorption and refraction behaviors of a dil... more Using the Z-scan technique, we studied the nonlinear absorption and refraction behaviors of a dilute toluene solution of a silicon naphthalocyanine (Si(OSi(n-hexyl)(3))(2), SiNc) at 532 nanometer with both a 2.8-nanosecond pulse and a 21-nanosecond (HW1/eM) pulse train containing 11 18-picosecond pulses 7 nanosecond apart. A thermal acoustic model and its steady-state approximation account for the heat generated by the nonradiative relaxations subsequent to the absorption. We found that when the steady-state approximation satisfactorily explained the results obtained with a 21-nanosecond pulse train, only the thermal-acoustic model fit the 2.8-nanosecond experimental results, which supports the approximation criterion established by Kovsh et al.
Using the Z-scan technique, we find that migration of chloroaluminum phthalocyanine in liquid eth... more Using the Z-scan technique, we find that migration of chloroaluminum phthalocyanine in liquid ethanol can be induced by the absorption of a 19 ps laser pulse with energy exceeding a threshold but not by that of a 2.8 ns pulse depositing more energy at the solute molecules. Considering each solute molecule as an oscillator confined within a potential well, we explain, in accordance with the five-energy-band model, that solute molecules excited by a 19 ps pulse retain more translational excess energy to overcome the potential well barrier compared with those excited by a 2.8 ns pulse of equal energy. Therefore, they are more likely to migrate out of the laser beam center, weakening the solution's absorption that we detect in the Z-scan measurements. Furthermore, we theoretically infer that the 19 ps pulse-induced solute migration tends to be nonquasistatic and experimentally verify that it cannot be attributed to the Soret effect, a quasistatic process.
IEEE Journal of Selected Topics in Quantum Electronics, 1996
The coherent transient responses of two simple molecular liquids, CS2 and CHBr3, are studied at r... more The coherent transient responses of two simple molecular liquids, CS2 and CHBr3, are studied at room temperature with the technique of time-resolved pump/probe optical Kerr effect. Use is made of an ultrashort laser with pulsewidth varying from ⩾100 to 28 femtoseconds (fs). For both liquids the instantaneous electronic response is found to increase markedly relative to the delayed nuclear response
We present measurements of nonlinear absorption and refraction in semiconductors used in the real... more We present measurements of nonlinear absorption and refraction in semiconductors used in the realization ofoptical limiters. We show that nonlinear refraction at 532 nm in ZnSe is caused by a negative third orderelectronic Kerr effect in addition to the two-photon-...
Nonlinear absorptive and refractive properties of C60/toluene solution are studied using the Z-sc... more Nonlinear absorptive and refractive properties of C60/toluene solution are studied using the Z-scan technique and a 532 nm laser delivering single picosecond (ps) pulses and trains of ps pulses separated by 7 nanoseconds (ns). With single ps pulses, reverse saturable absorption and positive nonlinear refraction are observed and attributed to population transitions among the singlet states. With ps pulse trains,
The pump-probe Raman-induced optical Kerr effect (RIKE) of simple molecular liquids, studied with... more The pump-probe Raman-induced optical Kerr effect (RIKE) of simple molecular liquids, studied with femtosecond laser pulses, exhibit long lasting beats ascribable to vibrational quantum interference (QI). While energy conservation entails vibrational resonances in RIKE, momentum conservation boils down to wave vector-matching in the pump and probe processes, which calls for the participation of a vibrational excitation wave. The refractive index
2009 Conference on Lasers & Electro Optics & The Pacific Rim Conference on Lasers and Electro-Optics, 2009
1, Shuefu Rd., Nei-pu, Ping-tung 912, Taiwan, China .3Department of Construction Engineering, Nat... more 1, Shuefu Rd., Nei-pu, Ping-tung 912, Taiwan, China .3Department of Construction Engineering, National Yunlin University of Science and Technology, 123 University Rd., Section 3,Dou-liou, Yun-lin 640, Taiwan, China 1Email: phyjlt@.ccu.edu.tw; 3Email: wangjn@ ...
2009 Conference on Lasers & Electro Optics & The Pacific Rim Conference on Lasers and Electro-Optics, 2009
We present recent studies of negative lensing effect observed in several molecular liquids using ... more We present recent studies of negative lensing effect observed in several molecular liquids using Z-scan technique and 28 femtosecond 800 nm laser pulses. Raman induced Kerr effect and thermal lensing effect are invoked to explain the sign of nonlinear refraction.
2009 Conference on Lasers & Electro Optics & The Pacific Rim Conference on Lasers and Electro-Optics, 2009
Page 1. Nonlinear Absorption of InN Epitaxial Films Probed by Femtosecond Pulsed Transmission Z-s... more Page 1. Nonlinear Absorption of InN Epitaxial Films Probed by Femtosecond Pulsed Transmission Z-scan Measurements Tsong-Ru Tsai1, Tsung-Han Wu1, Jung-Cheng Liao1, Tai-Huei Wei2, Hai-Pang Chiang1, Jih-Shang Hwang1, Din-Ping Tsai3, and Yang-Fang Chen3 ...
Use was made of a novel Fabry–Pe´rot interferometer technique to determine the variation of refra... more Use was made of a novel Fabry–Pe´rot interferometer technique to determine the variation of refractive index with temperature (∂n/∂T) of a potassium niobate crystal with a GaAlAs diode laser. The transverse intensity distributions of the laser transmitted through the crystal were found to be temperature dependent, and the ∂n/∂T values along crystallographic b and c axes were determined to be −4.5×10−5 and 6.1×10−5 °C−1, respectively. The temperature changes required for tangential tuning from transverse mode TEMqmn to TEMqm+1n and sagittal tuning from TEMqmn to TEMqmn+1 were found to be 0.29 and 1.27 °C, respectively, when the laser was polarized along the b axis. When the laser polarization was along the c axis, the tangential and sagittal tunings were found to be 0.10 and 0.54 °C, respectively. These differences between the tangential and sagittal directions indicated that the monolithic ring resonator used was indeed asymmetric.
The principles of operation of semiconductor optical limiters which utilize two-photon absorption... more The principles of operation of semiconductor optical limiters which utilize two-photon absorption and free-carrier induced defocusing are described. We present a review of early work using psec pulses at 532 nm in ZnSe, in which the problem of damage in solid state limiters is overcome by optimizing the focusing geometry. Limiting energies as loW as 10 nJ are seen, and a dynamic range (damage energy divided by limiting energy) in excess of 104 is demonstrated. The somewhat complicated propagation theory is simplified into a set of scaling rules which are used to predict operating characteristics of semiconductor limiters at longer wavelengths and for shorter pulses. We present new limiting data obtained with longer pulses in ZnSe, in CdTe at 1.06 mum and InSb at 10.6 mum, and we compare these results with the scaling rules.
Using the Z-scan technique, we studied the nonlinear absorption and refraction behaviors of a dil... more Using the Z-scan technique, we studied the nonlinear absorption and refraction behaviors of a dilute toluene solution of a silicon naphthalocyanine (Si(OSi(n-hexyl)(3))(2), SiNc) at 532 nanometer with both a 2.8-nanosecond pulse and a 21-nanosecond (HW1/eM) pulse train containing 11 18-picosecond pulses 7 nanosecond apart. A thermal acoustic model and its steady-state approximation account for the heat generated by the nonradiative relaxations subsequent to the absorption. We found that when the steady-state approximation satisfactorily explained the results obtained with a 21-nanosecond pulse train, only the thermal-acoustic model fit the 2.8-nanosecond experimental results, which supports the approximation criterion established by Kovsh et al.
Using the Z-scan technique, we find that migration of chloroaluminum phthalocyanine in liquid eth... more Using the Z-scan technique, we find that migration of chloroaluminum phthalocyanine in liquid ethanol can be induced by the absorption of a 19 ps laser pulse with energy exceeding a threshold but not by that of a 2.8 ns pulse depositing more energy at the solute molecules. Considering each solute molecule as an oscillator confined within a potential well, we explain, in accordance with the five-energy-band model, that solute molecules excited by a 19 ps pulse retain more translational excess energy to overcome the potential well barrier compared with those excited by a 2.8 ns pulse of equal energy. Therefore, they are more likely to migrate out of the laser beam center, weakening the solution's absorption that we detect in the Z-scan measurements. Furthermore, we theoretically infer that the 19 ps pulse-induced solute migration tends to be nonquasistatic and experimentally verify that it cannot be attributed to the Soret effect, a quasistatic process.
IEEE Journal of Selected Topics in Quantum Electronics, 1996
The coherent transient responses of two simple molecular liquids, CS2 and CHBr3, are studied at r... more The coherent transient responses of two simple molecular liquids, CS2 and CHBr3, are studied at room temperature with the technique of time-resolved pump/probe optical Kerr effect. Use is made of an ultrashort laser with pulsewidth varying from ⩾100 to 28 femtoseconds (fs). For both liquids the instantaneous electronic response is found to increase markedly relative to the delayed nuclear response
We present measurements of nonlinear absorption and refraction in semiconductors used in the real... more We present measurements of nonlinear absorption and refraction in semiconductors used in the realization ofoptical limiters. We show that nonlinear refraction at 532 nm in ZnSe is caused by a negative third orderelectronic Kerr effect in addition to the two-photon-...
Nonlinear absorptive and refractive properties of C60/toluene solution are studied using the Z-sc... more Nonlinear absorptive and refractive properties of C60/toluene solution are studied using the Z-scan technique and a 532 nm laser delivering single picosecond (ps) pulses and trains of ps pulses separated by 7 nanoseconds (ns). With single ps pulses, reverse saturable absorption and positive nonlinear refraction are observed and attributed to population transitions among the singlet states. With ps pulse trains,
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