Ammonium dihydrogen phosphate (ADP) has the same crystal symmetry as KDP

PHYSICS · Multi-part · Fermi University Physics · Optics & Photonics · Polarisation and anisotropic media · Polarisation and anisotropic media

What an Instrument Can See, Ch Modulating light: electro-optic, acousto-optic and magneto-optic devices

Problem

Ammonium dihydrogen phosphate (ADP) has the same crystal symmetry as KDP, so with the field along the optic axis only

r_{63}

acts. For ADP,

n_o = 1.52

and

r_{63} = 8.5\,\mathrm{pm\,V^{-1}}

. A field

E_z = 3.0\,\mathrm{MV\,m^{-1}}

is applied along the optic (

z

) axis. ((a)) State the angle through which the

x

and

y

axes of the index ellipsoid must be rotated to diagonalise the perturbed ellipsoid, and write the resulting expression for

\Delta n

in terms of

n_o

r_{63}

and

E_z

. ((b)) Compute the two new principal refractive indices

n_{x'}

and

n_{y'}