Photodiode Sensors
1919-R User Manual
40
shows a sample Bargraph showing laser power measurements, including
range, wavelength, filter, and average values. In this display, you can press
(Click the above links for more details.)
Figure
6-2 Photodiode Bargraph
6.3
Averaging and Measuring Very Low Power Measurements
If the laser power is fluctuating, the 1919-R can display the average power readings with averaging
periods varying from 1s to 1 hour. When measuring very low powers, such as picowatt
measurements, there will be a rather large zero offset coming from the detector as well as a
considerable noise fluctuation. Nevertheless, you can measure these low values by using the
average function and pressing offset to eliminate the detector zero offset.
To measure very low powers:
1.
Press
Menu
and select
Functions
. Choose the appropriate value you want to
Average
over,
save it, and then
Exit
.
2.
Block the power source you wish to measure, wait for a few measurement periods and press
Offset
to subtract the zero offset.
3.
Unblock the power source and measure.
For a detailed description of the average function, see
Note:
The Average function does not work with autorange or dBm scales.
6.4
Measuring Total Exposure
For Photodiode sensors, measuring total exposure is based on summing Photodiode power
measurements over time.
In Exposure mode, 1919-R measures 15 times per second, updating the exposure displayed on the
screen 5 times per second.
