horiba FluoroMax-3, Operation Manual, Page: 136 / 220

FluoroMax-3 v. 3.1 (6 Mar 2006) Automated Polarizers
10-2
Note:
In some literature, the G factor is
defined as the
inverse
of Equation 3.
Therefore, some equations derived in
this manual may differ from other
sources.
ented polarizers (H) are said to be at 90°. Polarization and anisotropy are expressed as
follows:
P
I I
I I
=
−
+
VV VH
VV VH
(1)
r
I I
I I
=
−
+
VV VH
VV VH
2
(2)
In a real optical
system, the G , or grating factor , must be included to correct for the
wavelength response to polarization of the emission optics and detectors. The G factor
is defined as:
G G
I
I
= =
( )
λ
EM
HV
HH
(3)
The
G factor is primarily a
function of the wavelength of
the emission spectrometer. The spectral bandpass of the emission also affects
G . Thus,
a pre-calculated G factor can be applied to experiments in which instrumental factors
(emission wavelength and emission bandpass) are kept constant throughout the entire
experiment. In experiments where constant emission wavelength and bandpass is im-
practical, such as in emission anisotropy spectra, the
G factor must be measured by re-
cording I
HH
and I
HV
during the experiment at each emission wavelength.
Polarization in a spectrofluorometer is defined as:
P
I G I
I G I
I I
I I
I I
I I
=
− ∗
+ ∗
=
∗
∗
−
∗
∗
+
VV VH
VV VH
VV HH
VH HV
VV HH
VH HV
1
1
(4)
Anisotropy in a spectrofluorometer is defined as:
r
I G I
I G I
I I
I I
I I
I I
=
− ∗
+ ∗
=
∗
∗
−
∗
∗
+
VV VH
VV VH
VV HH
VH HV
VV HH
VH HV
2
1
2
(5)
Polarization and anisotropy can be interconverted using these two equations:
P
r
r
=
+
3
2
(6)