Preferred Label : polarization;
Detailed label : polarization, P;
IUPAC definition : The relevant material property that couples with the radiation field. May be called
optical or dielectric polarization. Optical spectroscopies may be classified according
to the dielectric polarization power-law dependence on the external electric field.;
Scope note : the polarization component to the nth-order in the field is denoted as p(n) thus,
the following equations apply, p p(1) pnl and pnl
p(2) p(3) … p ¿0 ¿e(1) e
1/2 ¿e(2) e2 1/6 ¿e(3) e3 …
p(1) p(2) p(3) … where eiis the i-th component of the electric field strength
and¿e(n)is the usual susceptibility ¿(1) ¿r 1 in the absence of
higher terms and p(n) is the order of the field-induced polarization in the material.in
an anisotropic medium, ¿e(1),¿e(2)and ¿e(3) are the medium hyper-susceptibilities;
they are tensors of rank 2, 3, and 4, respectively.linear optical responses such as
absorption, light propagation, reflection, and refraction, involving a weak incoming
field, are related to p(1). non-linear techniques are connected to the non-linear
polarization pnl. low order non-linear techniques, such as three-wave mixing, are
related to the second order optical polarization p(2). for a random isotropic medium
(such as a liquid) or for a crystal with a centrosymmetric unit cell,¿e(2) is zero
by symmetry and then the lowest order non-linear techniques, as well as the higher
order, are related to the third-order optical polarization, p(3), and the corresponding
hyper-susceptibility.; mathematically it is defined as the electric dipole moment change per volume resulting
from absorption of radiation of optical frequencies, defined as p d
¿0 e ,where d is the electric displacement,¿0the electric constant (vacuum
permittivity) , and ethe strength of the radiation electric field. a dielectric medium
is characterized by the constitutive relation d ¿0 ¿(1) where
¿(1) ¿r 1 is the linear susceptibility for a transparent singly refracting
medium. depending on the molecular or atomic restoring force on the electron with
respect to the displacement d, the field-induced motion of the electron can introduce
other frequency components on the electron motion, and this in turn leads to non-linear
optical effects.;
Origin ID : P04712;
Automatic exact mappings (from CISMeF team)
- See also
The relevant material property that couples with the radiation field. May be called
optical or dielectric polarization. Optical spectroscopies may be classified according
to the dielectric polarization power-law dependence on the external electric field.
