Measurement of birefringence for optical recording of disk substrates

Abstract

Abstract

<title>Fast birefringence measurement using right and left hand circulary polarized laser</title>

“…(2), the DC component I and the quadrature AC components of beat signal J,, and are given by 'DC a?, (3) Ix = ar al L cos 2p, (4) ly = ar a A sin 2p. (5) In Eq. (3), (4) and (5), since we can adjust to the equal amplitudes ofleft and right circular polarization components; ie a1 = a,, then A and p of the sample are calculated as follow,…”

A Novel Method for Measuring the Vertical Birefringence of Optical Disk Substrates

“…Several authors have reported on the measurements of birefringence (both lateral and vertical) using various ellipsometric techniques. [5][6][7][8] These measurements tend to be elaborate, time-consuming, and confined to probing one small area at a time. Most often, these measurements are also intrusive in that they either slice and destroy the substrate, or render it unsuitable for further processing by the application of index-matching fluid during the measurement.…”

“…In (b) the At λ = 633 nm and with a measured pe riod of L = 1.05 mm, the above formula yields Δn⊥ -6 X 10 -4 , which is consistent with other measurements of the same substrate. 8 The period of oscillations can be derived fairly accurately from a Fourier spectrum of the intensity patterns of Figure 2. Figure 3 shows the spectrum of the signal displayed in Fig.…”

Vertical Birefringence Characterization for Optical Polymer Films

“…Mansuripur's group [8][9][10] has developed techniques to measure both in-plane and vertical birefringence of an optical disc. This technique extracts the birefringence measuring polarization variations and fitting these to models generated in Multilayer system analysis software, without giving the explicit relation between the polarization variation and birefringence.…”