(a) A sucrose solution has specific rotation at the sodium D line, meaning that light…

PHYSICS · Subjective · Fermi University Physics · Optics & Photonics · Polarisation and anisotropic media · Polarisation and anisotropic media

What an Instrument Can See, Ch Anisotropic media: the dielectric tensor and the index ellipsoid

Problem

(a) A sucrose solution has specific rotation

[\alpha] = 66.5^\circ\,\mathrm{mL\,g^{-1}\,dm^{-1}}

at the sodium D line, meaning that light rotates by

[\alpha]\times c \times l

degrees for a solution of concentration

c

(in

\mathrm{g\,mL^{-1}}

) over a path length

l

(in dm). Estimate the optical rotation produced by a

20\%

w/v sucrose solution (

c = 0.20\ \mathrm{g\,mL^{-1}}

) in a

10\ \mathrm{cm}

polarimeter cell. (b) A glass sample of thickness

5.0\ \mathrm{mm}

has stress-optic coefficient

C = 2.5\times10^{-12}\ \mathrm{Pa^{-1}}

; the optical path difference it develops under a uniform stress

\sigma

C\sigma d

. A Berek compensator used to null the induced retardance can resolve an optical path difference of

4\ \mathrm{nm}

. Estimate the smallest stress it can detect in this sample.