| 摘要 |
PURPOSE:To decrease the number of optical parts of a device and to improve the linearity of oscillation detection by stressing an photoelastic element so that a phase difference of 1/4 wavelength is generated. CONSTITUTION:When the oscillation directions of linear polarized light waves of a polarizer 3 and an analyzer 7 are made parallel, the intensity relation between the phase difference of the photoelastic element 4 and rays of light after passing through the analyzer 7 is expressed by I=1/2I0(1+Cosdelta) (I0: light intensity when the phase difference is '0', I: light intensity when the phase difference is delta). When the phase difference is a quarter as large as wavelength, delta=pi/2 and Cosdelta=0, so I=1/2I0. Namely, the phase difference of 1/4 wavelength is irrelevant to the shape of the photoelastic element 4 and obtained by increasing a load by tightening a bolt 12 until the light intensity detected through an optical fiber 8 is reduced to a half as large as when the photoelastic element 4 is not loaded. Consequently, the number of optical parts of the device is decreased and the linearity of oscillation detection is improved.
|
