High resolution, high sensitivity gas analyzer using a wide-band tunable CO_2 laser

Research Project

Project/Area Number	09555017
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Single-year Grants
Section	展開研究
Research Field	Applied optics/Quantum optical engineering
Research Institution	Nara National College of Technology
Principal Investigator	MATSUSHIMA Tomoshi Nara National Col.of Tech.Elec.Engi., Professor, 電気工学科, 教授 (50165817)
Co-Investigator(Kenkyū-buntansha)	CHO Yoshio Oyokoden Laboratory, Adviser, 顧問 SUETA Tadasi Setsunan University Depart.of Engi., Professor, 工学部, 教授 (20029408)
Project Period (FY)	1997 – 1998
Project Status	Completed (Fiscal Year 1998)
Budget Amount *help	¥6,500,000 (Direct Cost: ¥6,500,000) Fiscal Year 1998: ¥1,000,000 (Direct Cost: ¥1,000,000) Fiscal Year 1997: ¥5,500,000 (Direct Cost: ¥5,500,000)
Keywords	Fabry-Perot interferometer / Waveguide CO_2 laser / White mirror type gas absorption cell / CdTe electrooptic crystal / HgCdTe photodetector / Wide-band tunable CO_2 laser / High resoluble、high sensitive gas absorption cell / 進行波形光変調器 / ファブリ・ペロー形干渉計 / 広帯域周波数可変導波形炭酸ガスレーザ / CdTe電気光学結晶 / ファブリ・ペロ-形干渉計
Research Abstract	Characteristics of the material peculiar absorption wavelength may be utilized for the measuring method of types and concentration such as the pollutant which exists in the atmosphere. Wide-band tunable CO2 laser and high-resolution absorption cell are required when this method is utilized. An experimental analytical equipment system was constructed, The system consists of four componennts. The first one is a wideband tunable CO_2 laser by combining a waveguide CO_2 laser with CdTe traveling wave wideband electrooptic phase modulator. A single frequency line selectable C0_2 laser and a wide-bannd electrooptic travelingwave phase modulator were constructed. The modulator has been composed of the CdTe modultion element (2mmx2mmxl5mm) divided in five in order to enable the wide-bannd modulator. It is possible that the modulator composed of divided modulation element achieves the wide-band modulation by adjusting the phase of microwaves between sections . The microwave transmission characteristics bandwidth of the modulator was 10GHz for one element. The second one is a high resoluble, high sensitive gas absorption cell. High resoluble high sensitive gas absorption cell which inserted the white mirror (mirror interval 2Ocm, mirror reflectivity 99.7%) in the Fabry-Perot interferometer (mirror interval 6Ocm, mirror reflectivity 98%) was constructed and tested, and 1MHz resolution was obtained. The last one is an JR HgCdTe photodetector and a storage oscilloscope.