33
1.0
0.8
0.6
0.4
0.2
0.
0
VOL
TS
0.
0
0
0.02 0.04 0.06 0.08 0.10
TIME (sec)
V
peak
Figure 12 – Typical Newport Energy Detector Signal Waveform - An energy
detector signal sharply rises to a peak value and then decays going some-
what negative before finally returning to zero. The energy in the radiant
pulse is proportional to the height of the peak measured from immediately
before the sharp rise.
1.0
0.8
0.6
0.4
0.2
0.
0
VOL
TS
0.
0 0.2 0.4 0.6 0.8 1.0
TIME (sec)
V
peak
Figure 13 – Negative Baseline Voltage Due to a Pulse Train - If a laser pulse
arrives before the previous Energy detector signal has fully decayed, the
detector signal rises from the present decay point of the previous signal.
3.7
Peak-to-Peak (Photodiode) Detector Signals
The Model 2835-C allows one to make peak-to-peak measurements of time
varying signals from semiconductor photodiode detectors. Since optical
power is a zero bounded positive quantity, signals from a detector observing
such modulated light will similarly be zero bounded positive signals. To make
a peak-to-peak measurement, the Model 2835-C must be able to capture both
the maximum and minimum values of a detector signal. This is accomplished
by AC coupling the incoming detector signal so that the original minimum
value shows up as a negative peak.
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