ISSN:
1089-7623
Source:
AIP Digital Archive
Topics:
Physics
,
Electrical Engineering, Measurement and Control Technology
Notes:
A frequency shift of ω1F/2π=1.45 MHz is obtained for a 337-μm HCN laser beam by use of a rotating grating fabricated on the top of the rotor of a turbomolecular 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 far-infrared laser. The frequency-shifted beam is slightly frequency modulated (modulation index Mf(approximately-equal-to)1.2) with a period equal to the rotation period of the grating. This frequency modulation does no harm to these diagnostics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.1142118
