Gentec-EO QE and XLE4 - Manual (Page 25)

QE Series Joulemeter Instruction Manual Version 3.0 April 2014 25
2.1.2 Working at other wavelengths than 1.064µm (except with QED
attenuator / diffuser)
The monitor will automatically configure himself using the data stored in the EEPROM of
the DB-
15 “Smart Interface”. This includes the calibration sensitivity and wavelengths
corrections for 20 current wavelengths 7 8 .
For more precise measurements with a QE Series
joulemeter at wavelengths other than
those already corrected by the “Personal wav25avelengthrrection TM ” 7 data programmed
into the “Smart Interface”, a correction factor 8 must be set in the monitor to compensate for
the change in sensitivity of the joulemeter caused by the change in absorption of the optical
absorber at different wavelengths.
To correct for the change in absorption refer to the spectral curve of the “ Personal
Wavelength Correction
TM “ certificate supplied for the joulemeter and calculate K by taking
the percentage difference between the absorption @1.064µm and that at the desired
wavelength.
 
 
μm 064 . 1 @
1
A
A
K


Here
 
1

A = Absorption of the QE @ the desired wavelength.
 
μm 064 . 1 @ A = Absorption of the QE @ 1.064µm
A sample calculation follows:
 
1

A = 92 %.
 
μm 064 . 1 @ A = 94 %
K =
 
 
μm 064 . 1 @
1
A
A

x 100
K =
% 94
% 92
x 100 = 0.9787 x 100 = 97.87 %
and is the Correction Factor to be set in the monitor
8
.
7 Refer to t he spectral curve of the “ Personal Wavelength Correction TM “ certificate supplied with the
joulemeter
8 Refer to the monitor manuals for instructions.