Nonlinear Optical Properties of Cesium Atom
碩士 === 國立成功大學 === 物理學系碩博士班 === 98 === In this thesis, a typical Z-Scan system was constructed to measure the self-lensing effect in Cs vapor. The refractive nonlinearity (self-focusing or self-defocusing) can be observed by detecting the transmittance of the laser power that goes through an apertu...
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| Format: | Others |
| Language: | zh-TW |
| Published: |
2010
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| Online Access: | http://ndltd.ncl.edu.tw/handle/53178499616131122072 |
| Summary: | 碩士 === 國立成功大學 === 物理學系碩博士班 === 98 === In this thesis, a typical Z-Scan system was constructed to measure the self-lensing effect in Cs vapor. The refractive nonlinearity (self-focusing or self-defocusing) can be observed by detecting the transmittance of the laser power that goes through an aperture.
In a two-level system, the nonlinearity is related to the detuning and the vapor density of the Cs atoms. In this experiment, the temperature of the Cs cell is thermal stabilized at 80 and the frequency of external cavity diode laser was locked on the Cs hyperfine transition ( ). The frequency of the laser beam to the Cs cell can be tuned by Acousto-Optic Madulator to around 400MHz from the resonance.
The phenomenon of self-focusing effect was observed when the frequency of the laser light was blue-detuned from the levels, and the red-detuning light gave the result of self-defocusing effect. The strength of the nonlinearity is proportional to the intensity of the incident light. The value of the second order of index of refraction id derived from the observed data to be under the condition of Cs cell at 80 and laser frequency at +496MHz blue detuning from the Cs line.
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