| 摘要 |
1292205 Polarizing apparatus PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd 30 Jan 1970 [3 Feb 1969] 4632/70 Addition to 1245760 Heading G2J [Also in Division H4] Relates to apparatus for converting linear polarized light having an arbitrary plane of polarization into linearly polarized light having a plane of polarization which rotates at a substantially constant angular velocity, the apparatus including a series of birefrigent elements at least one being an electro-optic crystal. In a first embodiment, Fig.1, plane polarized light passes through semi-transparent mirror 4 and the series arrangement of electro-optic crystals 5 and 8 exhibit the Pockels effect and is then reflected byaretrodirective element 11 e.g. a plane mirror or a "cat's eye" (lens and a plane or concave mirror), back through the electro-optic crystals being reflected by the mirror 4 to a photo-electric detection system 12. The principal directions of crystals 5 and 8 (indicated by arrows 6 and 9) are at 45 degrees to each other, and an alternating voltage V 1 = Vsin wt. is applied to crystal 5 and an alternating voltage V 2 = V'cos wt. is applied to crystal 8, the peak voltage amplitudes V and V' being such as to result in quarter wavelength phase differences. This apparatus is equivalent to the apparatus shown in Fig. 1 in the parent Specification, and apparatus referred to which includes (2n-1) crystals may be replaced by apparatus which includes n crystals followed by a retrodirective element according to the present invention. An apparatus equivalent to that of Fig. 4 (not shown) of the parent Specification is described with reference to Fig.2 (not shown). |
