Electro-optical method for polarimetric measurement

摘要

When passing a pulsing beam of polarize light of a light emitter diode (LED) or a semiconductor laser thru an optical system and two photodiodes spatially arranged at 90° to each other and both with their detection surfaces parallel to the transmission shaft of light, and polarization axis oriented at 45° of the vertices of the edges where the photodiodes join, in the outputs of two operational amplifiers, e have two signals with the same shape in time, i.e. a pulse train with the same phase, but when you turn the polarization plane, change the radiance of the light projected onto the photodiodes, being out of phase signals to the outputs of the amplifiers, where the difference between the fronts of the pulses is proportional to the angle of rotation of the plane of polarization of polarization light. In a digital circuit phase discriminator, a puls e is obtained equal to the time difference between two sides of the rise time in the output of two amplifiers. The width of this is directly proportional to the value of rotation the plane of polarization of light, that is, the greater the rotation, the greater the width of this.