Working at other wavelengths than 10.6µm – Gentec-EO THZ-D User Manual

Page 12

Revision 1.1

THZ-D Series Instruction Manual

3- Remove the detector's protective cover, when applicable.

4- The THZ9D requires the use of an Optical Chopper running at 10 Hz. Place the optical

chopper (SDC-500 or equivalent) into the laser beam path between the laser and the
THZ9D. Make sure that the laser beam is fully contained within the 9 mm detector
aperture.

CAUTION: Be careful not to exceed the maximum levels and densities in: energy, peak

power and average power as stated in the specifications pages.

NOTE:

As with all thermopile or pyroelectric devices, these detectors have some position
and beam size linearity. 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
power (of a semi-Gaussian beam stopped at 1/

) applied to a diameter equal to

80% of the detector aperture. If you use of a divergent lens, a Lambertian diffuser,
or any other method of beam spreading, please take note that all of the laser light
must be directed within the detector aperture and that the optical losses must be
known. The measurement must then be corrected to compensate for these
losses.

3.2 Working at other wavelengths than 10.6µm

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 wavelength

corrections for 20 current wavelengths

8 9

For more precise measurements with a THZ-D Series

detectors at wavelengths other than

those already corrected by the typical

“Personal wavelength correction

’’

data

programmed into the “Smart Interface”, a correction factor

is automatically set in the

monitor to compensate for the change in sensitivity of the wattmeter caused by the change
in absorption of the optical absorber at different wavelengths. This automatic correction is
a linear interpolation between two measured values of the typical

‘’Personal wavelength

correction’’.

Refer to the spectral curve of the typical “ Personal Wavelength Correction

“ certificate at section 8

Refer to the monitor manuals for instructions.