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Development and transmission measurement of an ultra-narrow optical band pass filter for sodium lidar daytime observations

用于钠激光雷达日间观测的超窄光学带通滤波器的开发和传输测量

基本信息

批准号：
17340144
负责人：
KAWAHARA Takuya
金额：
$ 3.48万
依托单位：
Shinshu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

项目摘要

Summary of this research based on the fund is as followed.Developing a new sodium cell for a Faraday filter with the stable material against high temperature sodium vapor:A commercial type Pyrex-glass sodium cell does not work well when the cell is heated and sodium vapor is activated. We developed a Sapphire sodium cell using the special technique, optical contact method Sapphire is extremely stable against strong acid or base as well as sodium vaporEstablishing the procedure to measure transmissions of ultra-narrow optical band-pass filter with ring dye laser:The transmission width of a Faraday filter is about 10 pico meter that an ordinary spectrometer cannot resolve. The transmission measurement was done with a ring dye laser as an ultra-narrow light source at Tokyo Metropolitan University to precisely scan the transmission profile. The measured profile was reasonable but the results suggest the effective temperature is 10 degree lower than the monitored value.Doppler free spectrum measurements for absolute frequency measurements:Doppler free technique is the absolute frequency monitoring system around sodium D2 line using a sodium cell. By warming the laser with a special optical configuration, the spectrum was measured and the absolute frequencies were determined. This is necessary to determine the absolute frequency when the Faraday filter transmission is measured.Lidar receiving system with optical fibers:Optical fiber system is designed for the Mar receiving system bemuse strong magnetic field of Faraday filter affects the photoelectric detection using a photomultiplier tube. Designing an optical alignment with lenses was done and the efficiency was measured without Faraday filter The efficiency is 1/3 of the common system. Faraday filter may decrease the signal to 1/4. The results show the signal intensity decreases to roughly 1/10 in daytime.

本研究的主要内容如下：研制一种新型的耐高温钠蒸气的法拉第滤光片用钠电池：一种商用的Pyrex玻璃钠电池，在电池加热和钠蒸气活化时不能很好地工作。我们采用特殊的光学接触法，研制了蓝宝石钠池。蓝宝石对强酸、强碱和钠蒸气都非常稳定。建立了用环形染料激光器测量超窄带滤光片透过率的方法：法拉第滤光片的透过宽度约为10皮科米，这是普通光谱仪无法分辨的。透射率测量是在东京首都大学用环形染料激光器作为超窄光源进行的，以精确扫描透射率分布。测得的剖面是合理的，但结果表明，有效温度比监测值低10度。用于绝对频率测量的无多普勒频谱测量：无多普勒技术是使用钠电池的钠D2线周围的绝对频率监测系统。采用特殊的光学结构对激光器进行加热，测量了光谱，确定了绝对频率。光纤激光雷达接收系统：由于法拉第滤波器的强磁场影响光电倍增管的光电探测，设计了光纤激光雷达接收系统。设计了一种带透镜的光学准直系统，并在不加法拉第滤光片的情况下进行了效率测试，效率为普通系统的1/3。法拉第滤波器可以将信号降低至1/4。结果表明，信号强度在白天下降到约1/10。