Abstract:
An optical beam is injected into a single-mode (FO) fibre of a given length and outgoes from an end face of the fibre, is reflected by a reflecting optical system into said fibre; the optical power of the reflected beam guided backward by the fibre is measured. Said end face of the fibre is placed in the optical centre of the reflecting system to obtain the maximum reflected power, and is then deviated from said position detecting the occurring reductions of the reflected optical power.A device and variants to implement the method are also described.
Abstract:
A static interferometric ellipsometer, wherein a source (3) generates a coherent light-beam with two monochromatic radiations at slightly different frequencies. A first photodetector (6) generates a first beat between the two radiations, to be used as reference. A second photodetector (9) generates a second beat between the two radiations, after they have been polarized in perpendicular planes and separated so that one of them is reflected onto the photodetector (9) by the sample under test (1,2). A measuring and computing system (11) determines the optical properties of said sample starting from the intensity of the second beat and from the relative phase between the two beats.