User:Steven J. Koch/Notebook/Kochlab/2009/08/11/Noise
Steve Koch 16:14, 11 August 2009 (EDT): The beam expander seems exceptionally unstable & produces noise in X, Y, and Sum, and also seems possibly the cause of the sudden jumps in sum and x&Y
Steve Koch 16:31, 11 August 2009 (EDT): Another very strange thing:
- With power modulator out of range (low; 18.81 mW and "error" on the front panel), the sum signal is stable with a noise level of about 2 millivolts (0.116 to 0.118)
- With power modulator in range (27.88 mW), the sum signal is much noisier: 196 to 206 mV. But at this power, the sum signal is not sensitive at all to beam expander touching.
- Up at higher powers, the sum signal becomes more sensitive to vibration.
I am thinking this may mean we need an isolator in between laser and other elements.