%0 Journal Article
%T A Z-Scan Theory Based on Diffraction Theory with Consideration of Two-photon Absorption<br>以衍射理论为基础考虑双光子吸收的Z-扫描理论
%A ( College of Physics
%A Information Optic-electronics
%A Henan University
%A Kaifeng ( State Key Laboratory of Transient Optics
%A Photonics
%A Xi''an Institute of Optics
%A Precision Mechanics
%A Chinese Academy of Sciences
%A Xi''an
%A <br>李 霞
%A 姚保利
%A 侯洵
%J 光子学报
%D 2005
%I 
%X Based on Fresnel-Kirchhoff diffraction theory, a diffraction model of a nonlinear optical medium to a Gaussian beam is built. The propagation behavior of the Gaussian beam passing through the nonlinear optical medium is theoretically deduced and numerically simulated, which can explain the Z-scan phenomenon from a new approach. From this theory, a unified equation is derived, which can describe both the closed-aperture Z-scan curve and the open-aperture Z-scan curve with consideration of the twophoton absorption. It provides a new way to calculate the nonlinear refraction index and the two-photon absorption coefficients. Numeric simulation shows that for the closed-aperture Z-scan considering the twophoton absorption, the simulation results are well consistent with the conventional theory. For a given open-aperture Z-scan curve, the two-photon absorption coefficient computed by the new Z-scan theory is 1/3 of the value fitted by the conventional Z-scan theory, whereas other conclusions are identical to the conventional Z-scan theory. This theory has better accuracy than the conventional Z-scan theory because the approximate conditions are only thin sample and small nonlinear absorption.
%K Z-scan
%K Nonlinear refractive index
%K Two-photon absorption
%K Diffraction
%K Optical Kerr effect<br>Z-扫描
%K 非线性折射率
%K 双光子吸收
%K 衍射
%K 光克尔效应
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=6E709DC38FA1D09A4B578DD0906875B5B44D4D294832BB8E&cid=47EA7CFDDEBB28E0&jid=9F6139E34DAA109F9C104697BF49FC39&aid=D98FF019D47C107B&yid=2DD7160C83D0ACED&vid=339D79302DF62549&iid=DF92D298D3FF1E6E&sid=BF1CF7F9466F9169&eid=512771C17A2FFC1B&journal_id=1004-4213&journal_name=光子学报&referenced_num=2&reference_num=7