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Development and application of infrared laser excitation spectroscopy with an array detector

阵列探测器红外激光激发光谱的研制与应用

基本信息

批准号：
13440181
负责人：
KAWAGUCHI Kentaro
金额：
$ 8万
依托单位：
OKAYAMA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

项目摘要

In the present study we had an aim to construct a spectroscopic system to detect infrared emission with high sensitivity. So far infrared emission has been observed mainly by Fourier transform spectroscopic method. However, the method is limited to species such as diatomic molecules mainly. Since the probability of emission in the infrared region is not high, we considered laser excitation spectroscopy to observe induced emission, where an infrared laser is used to saturate a vibration-rotational transitions of molecules.One of advantages of the present study is to rise an infrared array detector to observation of weak emission spectra. An infrared array detector with InSb X56 x 256 elements was installed in a dewar of 35 K. Data from the detector were read out by using COGITO-3 system and transferred to a work station and analyzed by an IRAF software. The detection system was coupled to a grating spectrometer to observe emission spectrum.For excitation source, an infrared diode laser system was set up by using commercially available laser elements which operate under low temperature of 12-80 K. The system was applied to absorption spectroscopy by using multi-path cell to determine isotopic abundance ratios of the atmospheric N_2O molecule.The output power of the diode laser was not enough for saturating vibration-rotation transitions, so a quantum cascade laser_(QC laser) is considered as the candidate of excitation source. We carried out a co-operative study with HAMAMATSU HOTONIKUSU to investigate the performance of the QC lasers. It was found that the output power was enough large (about 100 mW) for the present purpose and application to laser excitation spectroscopy has been carried out.

在本研究中，我们的目标是建立一个光谱系统，以检测红外发射具有高灵敏度。迄今为止，人们主要通过傅里叶变换光谱方法观测到远红外辐射。然而，该方法主要限于诸如双原子分子的物种。由于在红外区发射的几率不高，我们考虑用激光激发光谱来观察诱导发射，用红外激光来饱和分子的振动-转动跃迁，本研究的优点之一是将红外阵列探测器上升到弱发射光谱的观测。在35 K的杜瓦中安装了InSb X56 × 256红外阵列探测器。用COGITO-3系统读出检测器的数据，并将数据传输到工作站，用IRAF软件进行分析。探测系统与光栅光谱仪耦合，观测发射光谱;激发源采用红外半导体激光器，利用市售的低温激光元件，工作温度为12-80 K。该系统应用于大气N_2O分子同位素丰度比的多路吸收光谱测量，由于半导体激光器的输出功率不足以满足饱和振转跃迁的要求，因此选择量子级联激光器_（QC）作为激发源。我们与HAMAMATSU HOTONIKUSU进行了合作研究，以调查QC激光器的性能。结果表明，输出功率足够大（约100毫瓦），目前的目的和应用的激光激发光谱已进行。