摘要
为消除非共振背景干扰,提高相干反斯托克斯拉曼散射测量精度,研究了基于偏振探测的相干反斯托克斯拉曼散射非共振背景抑制与分离.首先,从理论上证明了相干反斯托克斯拉曼散射信号强度只取决于三阶非线性极化率共振部分,而与非共振部分无关,并且三阶极化率共振部分与非共振部分偏振方向不一致,为偏振相干反斯托克斯拉曼散射提供了理论支撑;然后,以平面火焰炉温度场为研究对象,设计了偏振相干反斯托克斯拉曼散射探测系统实施方案,并与热电偶、常规相干反斯托克斯拉曼散射两种方法在相同条件下开展了温度测量对比实验.实验结果表明:常规相干反斯托克斯拉曼散射方法的测量相对误差优于7%,测量相对不确定度优于7%;偏振相干反斯托克斯拉曼散射方法的测量相对误差优于4%,测量相对不确定度优于5%;相同工况条件下与常规相干反斯托克斯拉曼散射相比,偏振相干反斯托克斯拉曼散射最接近均值的拟合光谱更加平滑.偏振相干反斯托克斯拉曼散射具有更小的拟合误差,是一种更为有效的相干反斯托克斯拉曼散射诊断方法.
In order to get rid of non-resonant background interference and improve the measuring accuracy of Coherent Anti-Stokes Raman Scattering(CARS),polarized CARS detecting system was researched.First,the intensity of CARS was deduced of depending on the resonant part and independent of nonresonant part theoretically.Also,the resonant part and non-resonant part of third-order nonlinear polarizability were proved of having different polarized directions.All of the above formed the theoretical basis of polarized CARS.Second,polarized CARS detecting system was designed and temperature measuring tests were carried out on plain flame furnace by thermal couple,ordinary CARS and polarized CARS under the same work conditions.Experimental results suggest that the relative error of ordinary CARS is less than 7% while the polarized CARS′s is less than 4%,which are computed basing on thermal couple′s results.And,the relative uncertainty of polarized CARS is less than 5%,while the ordinary CARS′s is less than 7%.Furthermore,fitting spectrum of polarized CARS is more smooth than ordinary CARS′s at the same working mode.All of the analysis suggsts that polarized CARS detecting system is a more effective CARS method.
出处
《光子学报》
EI
CAS
CSCD
北大核心
2017年第S1期17-22,共6页
Acta Photonica Sinica
基金
国家自然科学基金(Nos.11272337
11272338)
高超声速冲压发动机技术重点实验室开放基金(No.STS/MY-KFKT-2015001)资助~~
关键词
光谱诊断
温度测量
相干反斯托克斯拉曼散射
非共振背景
偏振探测
Spectrum diagnosis
Temperature measurement
Coherent anti-Stokes Raman scattering
Non-resonant background
Polarized detection
