Gentec-EO QE and XLE4 - Manual (Page 26)

QE Series Joulemeter Instruction Manual Version 3.0 April 2014 26
Attention: when using QE series joulemeters with
QED attenuator / DIFFUSER:
2.1.3 Working with QED attenuator / diffuser.
Except when purchased on special order with a double factory calibration @1.064µm (with
and without attenuator), a so called V7 version, the data stored in the EEPROM of the DB-
15 “Smart Interface”, includes the calibration sensitivity and wavelengths corrections for 20
current wavelengths without the QED attenuator installed.
When using a double factory calibrated (@1.064µm) QE series joulemeter combined with a
When using a QE series joulemeter (@ any wavelength) with a QED attenuator, the user
must calibrate the attenuator; refer to “Calibration Procedure” document # 420-190068,
provided with the attenuator, for further details.
2.2 When using an oscilloscope:
2.2.1 General Instructions
1- Install tall the joulemeter on its optical stand
2- Connect the joulemeter to the oscilloscope.
NOTE: The required load impedance is 1 M

/ 30 pfd.
An optional DB-15 to BNC adaptor may be required when used in conjunction with an
oscilloscope. The C0 version is connected directly to oscilloscope.
3- Remove the detector's protective cover, when applicable.
4- Put the joulemeter head into the laser beam path (laser beam must be contained within the
aperture).
CAUTION: Be careful not to exceed the maximum levels and densities of, energy, peak
power and average power, stated in the specifications pages. The use of a
damage test target is strongly recommended.
WARNING: 1- At maximum average powers QE Series joulemeter bodies can reach 60°C
and can represent a burn hazard if handled with bare hands.
2- A diffuse back reflection of ~ 30% is present from the joulemeter’s optical
absorber.
NOTE: As with all large aperture pyroelectric devices, these detectors have some position
and beam size sensitivity. For the most accurate measurements, the beam should
normally be centered on the sensor surface and the beam diameter should ideally
be close to that of the original calibration conditions, which is 100% encircled
energy (of a semi-Gaussian beam stopped at 1/
e 2 ) applied to a diameter equal to
80% of the detector aperture. The use of a QED Attenuator/Diffuser 9 , a divergent
lens, a Lambertian diffuser such as opal glass, or any other method of beam
spreading, is recommended for this purpose. Please take note that all of the laser
9 See optional accessories section.