Part 1 Principles
Confocal Microscopy tutorial
Part 3 operation, optimization of Leica SP2 LSCM
Laser intensity adjusting and AOTF control
There are two ways to control laser intensity: One is by laser's power supply and another is AOTF control.
Power control knob: By power supply control knob on the switchboard, you can set the laser power from minimum to maximum. Higher power gives higher excitation thus higher emission and vice versa. But higher power consume more laser life time and produce more laser noise. So, a good starting point is at 10 o'clock position (about 30% of its maximum), then try adjust other parameter such as AOTF and PMT to get enough intensity. Reserve this as the last sorts if all others fail to deliver the intensity you need.
AOTF refers Acousto-Optical Tunable Filter which is an
adjustable quarts filter works at
frequency of as high as sound, that is "Acousto-". AOTF enable quick
on and off the laser, change laser lines and their intensity percentage by
setting it to 0% through 100%. The change is very quick and can be operated
on-line even during the scanning process. AOTF works like a filter in the light path, making certain percentage
High or low percentage in AOTF control does not affect laser power from
its source and does not change the laser noise level.
(In non-AOTF system, you have to stop the scan, change laser line in use, insert glass neutral density filter to attenuate the intensity, making automation impossible).
This page was last updated 23.03.2004