Streak Camera : Triggering

The photodiode

A little bit of the light of the Mira, is reflected with a transparent pellicle to the C1808-03 photodiode. [ a spare pellicle is in the cupboard. Thorlabs BP108].

It look like the pellicle works as an interference filter, so the reflection is lower at certain wavelengths.
Here is a graph of the percentage reflection (P-polarization. The laser is horizontally polarized) :

The green light at the side of the streak camera indicates if it gets triggered. If it is not on (and the mira is modelocked), open the variable OD-filter, or put the HP amplifier to 40 dB.

If there is too much trigger signal, it is also not good.
According to manual : “Instruction manual for universal streak camera C5680” , near end :
Light on photodiode : 500 micro-W = 5 mW @ 800 nm : output level : 1.5 V p-p in 50 Ohm

Single sweep

The Single sweep unit uses the trigger signal of the photodiode, but also a signal of the pulse picker. In the C4792-01 menu, the Trig.Mode should be set to Dump Mode !! Otherwise the green trigger light on the side of the streak camera just blinks once a second.

Display on scope

If the signal of the photodiode should be placed on the oscilloscope, then before disconnecting the coax from the photodiode, first the bias power should be turned off.