432-μm Laser’s Beam-waist Measurement for the Polarimeter/Interferometer on the EAST Tokamak
432-μm Laser’s Beam-waist Measurement for the Polarimeter/Interferometer on the EAST Tokamak
Z. X. Wang(Chinese Academy of Sciences); H. Q. Liu(Chinese Academy of Sciences); Y. X. Jie(Chinese Academy of Sciences); M. Q. Wu(Chinese Academy of Sciences); T. Lan(Chinese Academy of Sciences); X. Zhu(Chinese Academy of Sciences); Z. Y. Zou(Chinese Academy of Sciences); Y. Yang(Chinese Academy of Sciences); X. C. Wei(Chinese Academy of Sciences); L. Zeng(Chinese Academy of Sciences); G. S. Li(Chinese Academy of Sciences); X. Gao(Chinese Academy of Sciences)
65권 8호, 1215~1220쪽
초록
A far-infrared (FIR) polarimeter/interferometer (PI) system is under development for measurementsof the current-density and the electron-density profiles in the EAST tokamak. The systemwill utilize three identical 432-μm CHCOOH lasers pumped by a CO2 laser. Measurements of thelaser beam’s waist size and position are basic works. This paper will introduce three methods witha beam profiler and several focusing optical elements. The beam profiler can be used to show thespatial energy distribution of the laser beam. The active area of the profiler is 12.4 × 12.4 mm2. Some focusing optical elements are needed to focus the beam in order for the beam profiler toreceive the entire laser beam. Two principles and three methods are used in the measurement. Thefirst and the third methods are based on the same principle, and the second method adopts an otherprinciple. Due to the fast and convenient measurement, although the first method is a special formof the third and it can only give the size of beam waist, it is essential to the development of theexperiment and it can provide guidance for the choices of the sizes of the optical elements in the nextstep. A concave mirror, a high-density polyethylene (HDPE) lens and a polymethylpentene (TPX)lens are each used in the measurement process. The results of these methods are close enough forthe design of PI system’s optical path.
Abstract
A far-infrared (FIR) polarimeter/interferometer (PI) system is under development for measurementsof the current-density and the electron-density profiles in the EAST tokamak. The systemwill utilize three identical 432-μm CHCOOH lasers pumped by a CO2 laser. Measurements of thelaser beam’s waist size and position are basic works. This paper will introduce three methods witha beam profiler and several focusing optical elements. The beam profiler can be used to show thespatial energy distribution of the laser beam. The active area of the profiler is 12.4 × 12.4 mm2. Some focusing optical elements are needed to focus the beam in order for the beam profiler toreceive the entire laser beam. Two principles and three methods are used in the measurement. Thefirst and the third methods are based on the same principle, and the second method adopts an otherprinciple. Due to the fast and convenient measurement, although the first method is a special formof the third and it can only give the size of beam waist, it is essential to the development of theexperiment and it can provide guidance for the choices of the sizes of the optical elements in the nextstep. A concave mirror, a high-density polyethylene (HDPE) lens and a polymethylpentene (TPX)lens are each used in the measurement process. The results of these methods are close enough forthe design of PI system’s optical path.
- 발행기관:
- 한국물리학회
- 분류:
- 물리학