Browsing by Author "LIU, YM"

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AXIALLY PHASE-MATCHED PARAMETRIC 4-WAVE AND 6-WAVE MIXING IN POTASSIUM VAPOR
(1992-04-01)
LU, MH
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LIU, YM
;
交大名義發表
;
光電工程學系
;
National Chiao Tung University
Systematic experimental observations of axially phase-matched parametric four- and six-wave mixing processes have been made in potassium vapor pumped on or near the 4S-6S two-photon resonance. An IR up-conversion with a beta barium borate crystal was used for the detection of IR emissions. All the predicted processes have been observed. It is found that the excitation spectra of the emissions for those processes observed in this work are quite different from the excitation spectra of similar processes in sodium vapor. A dye-dependence of some emissions generated by the axially phase-matched parametric six-wave mixing processes has been found by using different dyes in the dye laser. The reason for the dye-dependence is discussed.
DYE-DEPENDENCE OF THE 830NM AND 1.16-MU-M EMISSIONS IN SODIUM VAPOR PUMPED NEAR THE 3S-4D 2-PHOTON RESONANCE
(1993-02-01)
LIU, YM
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LU, MH
;
交大名義發表
;
光電工程學系
;
National Chiao Tung University
The 830 nm and 1.16 mum emissions in sodium vapor which is pumped near 3S-4D two-photon resonance have been observed. It has been found that these two emissions are induced by the spontaneous emission of the dye R590, that provides the emissions near 584 nm, which as idle photons are coupled to the 830 nm and 1.16 mum emissions in the axially phase-matched six-wave mixing processes. This conclusion is based on the fact that the observed 830 nm and 1.16 mum emissions will almost disappear if the spontaneous emission of the dye R590 in the 584 nm wavelength range is blocked. As a result, the fluctuation and band-like structure in the emission spectra of the 830 nm and 1.16 mum lines can be understood to be due to the broad band and fluctuating in the spontaneous emission of the dye R590, and also due to the amplification in these generation processes that makes many unstable peaks in their spectra.
INFRARED UP-CONVERSION WITH BETA-BARIUM BORATE CRYSTAL
(1991-07-15)
LU, MH
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LIU, YM
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交大名義發表
;
光電工程學系
;
National Chiao Tung University
An IR up-conversion with a beta barium borate (beta-BBO) crystal as an upconverter has been made. The IR source at wavelengths 2.45-mu-m and 2.69-mu-m was provided by the lithium vapor excited by a pulsed dye laser tuned to the 2S-4S two-photon resonance of lithium atom. The phase matching angles for the type I phase matching has been measured and compared with the calculated values. Based on this comparison, the accuracy of various refractive index formulae extrapolated to the IR region is discussed. The IR up-conversion efficiency has also been measured which agrees reasonably with the calculation under a plane-wave approximation. The up-conversion with the beta-BBO crystal provides an effective approach for the IR detection in the 1-3-mu-m wavelength region.
OBSERVATION OF THE SUPPRESSION OF THE STIMULATED HYPER-RAMAN SCATTERING (S-3(1/2)-P-4(3/2)) NEAR THE SODIUM 4D 2-PHOTON RESONANCE
(1994-10-28)
LU, MH
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LIU, YM
;
交大名義發表
;
光電工程學系
;
National Chiao Tung University
The stimulated hyper-Raman scattering (SHRS) emissions associated with the excitation of the 4P(3/2) state in sodium vapour have been observed in both the forward and backward directions as the pumping laser was tuned near the 3S-4D two-photon resonance. The results show that though the forward SHRS process is greatly reduced by a destructive interference between it and the four-wave mixing (FWM) process induced by itself, the forward SHRS emission has a positive gain and can still be observed under a certain condition.
SUPPRESSION OF STIMULATED HYPER-RAMAN SCATTERING IN LITHIUM VAPOR
(1993-09-01)
LU, MH
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LIU, YM
;
交大名義發表
;
光電工程學系
;
National Chiao Tung University
The stimulated hyper-Raman scattering (SHRS) in lithium vapor has been observed in both the forward and the backward directions as the laser was tuned near the 2S-3S and 2S-4S two-photon resonances. It is found that in the forward direction the SHRS associated with the 2P excitation near the 2S-3S or the 2S-4S two-photon resonance is completely suppressed, but the SHRS associated with the 3P excitation near the 2S-4S two-photon resonance can be observed. A condition under which the forward SHRS takes place, given by Malakyan [3], has been examined. A reasonable agreement between the theory and the experiment is obtained. Near the 2S-3S two-photon resonance, instead of the expected emission omega2P-2S corresponding to the 2P-2S transition, an emission at the 2omega(P)-omega3S-2P frequency, which is close to the omega2P-2s, has been observed in the backward direction. The process generating this emission could be considered as an inverse SHRS process induced by the 3S-2P spontaneous emission. For the SHRS emission a shift of the observed frequency from the calculated frequency has been found. In order to explain the shift, the Stark effect has been calculated. The results show that the shift can not be attributed to the Stark effect.