Frequency Shift of Submm Waues with a Super Rotating Grating

使用超级旋转光栅实现亚毫米波的频移

• 批准号: 01880003
• 负责人: MAEKAWA Takashi
• 金额: $ 4.61万
• 依托单位: Kyoto University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Developmental Scientific Research (B).
• 财政年份: 1989
• 资助国家: 日本
• 起止时间: 1989 至 1990
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01880003/
• 关键词: Plasma Diagnostics; Rotating Grating; Submm Wave; Interferometer; Scattering Measuementr; プラズマ計測; HCNレ-ザ-; サブミリ波干渉計

1. Frequency shift of omega_<IF>/2pi=1.45 MHz is obtained for 337 mum HCN laser beam by use of a rotating grating fabricated on the top of the rotor of a turbo-molecular pump with a high rotating speed of 43200 rpm. (Super Rotating Grating). The frequency shift is one order higher than those with usual rotating gratings. Using this as a local beam, heterodyne detection of low frequency microturbulence as well as high time resolution interferometry in plasmas becomes possible with a single FIR laser.2. The frequency-shifted beam is slightly frequency-modulated (modulation index M_f<similar or equal>1.2) with a period equal to the rotation period of the grating. This frequency modulation does no harm to these diagnostics.3. The power conversion efficiency of the SRG measured with a pyroelectric detector is 0.2 for a teflon window and 0.25 for a crystal quartz window. We will increase the efficiency in a future work. The present efficiency may be, however, sufficient to carry out multichannel detection with a channel number of 10 or more, since 337 mum HCN lasers generate a large power.4. We intend to make a multi-channel interferometer of high time resolution as well as a scattering apparatus with heterodyne detection system by using the SRG and to study transport phenomena such as sawtooth oscillations and low frequency microtubulences in tokamak plasmas.

1.在转速为43200转/分的涡轮分子泵转子顶部制作了旋转光栅，获得了337um HCN激光的频率漂移。(超级旋转栅格)。其频移比通常的旋转光栅高一个数量级。利用这种局域光束，可以用单个FIR激光器外差探测等离子体中的低频微湍流以及高时间分辨率干涉测量。频移光束被轻微地调频(调制指数M_f&lt；类似或等于&gt；1.2)，其周期等于光栅的旋转周期。这种频率调制不会对这些诊断造成损害。用热释电探测器测量的SRG的功率转换效率，聚四氟乙烯窗口为0.2，石英晶体窗口为0.25。我们将在今后的工作中提高效率。然而，由于337微米HCN激光器产生大功率，因此目前的效率可能足以执行具有10个或更多通道数的多通道检测。我们打算利用SRG制作高时间分辨率的多通道干涉仪和外差探测的散射仪，并研究托卡马克等离子体中的锯齿振荡和低频微管等输运现象。

项目成果

T.Maekawa: "Freguency shift of 1.45MHz for 337ーμm HCN laser beam with a super rotating grating" Review of Scientific Instruments. 62. 304-307 (1991)

T. Maekawa：“具有超级旋转光栅的 337-μm HCN 激光束的 1.45MHz 频移”科学仪器评论 62. 304-307 (1991)。

T.Maekawa: "Frequency shift of 1.45MHz for 337μm HCN laser beam with a super rotating grating." Review of Scientific Instruments. 62. 304-307 (1991)

T. Maekawa：“具有超级旋转光栅的 337μm HCN 激光束的频移。” 科学仪器评论 62. 304-307 (1991)。

T. Maekawa, et al.: "Frequency Shift of 1.45 MHz for 337 mum HCN laser beam with a super rotating grating" Rev. Sci. Instrum.Vol 62 No 2. 304-307 (1991)

T. Maekawa 等人：“具有超级旋转光栅的 337 mum HCN 激光束的频移为 1.45 MHz”Rev. Sci。