Find the laser power control screen

• From the main EDM screen, choose "Laser" and "Laser Power"

• A screen will open up like this

Turn on the laser to normal operating point

• Press "Turn ON - High"
• This will turn on the laser amplifier and chiller, and slowly ramp the laser up to the High setpoint (currently 10 W)
• Please see below about usage after changing the laser setpoint

Turn on the laser to low power ("DC") operation

• Press "Turn ON - Low"
• The laser will turn on the amplifier and chiller, and ramp up to the low setpoint (currently 3 W)
• Even though the laser amplifier is set to "3 W", the actual power coming out of the laser is very nonlinear and at this setpoint will only be ~1 mW.
• Please see below about usage after changing the laser setpoint

Changing the laser setpoint power

• The shutter should be closed whenever changing the laser power
• Ideally, the gun is also off so there is no risk to the machine
• For about 1-5 minutes after changing the laser setpoint power, the pulse picker will be stabilizing its temperature, and may not function properly.
  • The extinction ratio of the laser may be very poor after doing this until it stabilizes again
  • The waveplates before the pulse picker have been set for a single laser power setting, and if you change setting-- say, from a High setpoint of 10W to 11 W-- then these waveplates will have to be adjusted to get a good extinction ratio again. This requires laser training to do so.
  • To be clear: if you change the laser power setting-- it would be wise to verify the laser is working correctly (power / extinction) on the laser power meter or viewscreen before using it on the gun.
• Running at the "Low" setpoint (<3.5 W) produces only ~1 mW of maximum laser power at the cathode. This is a safe setting for any duty factor, and EPICS will allow it to be increased up to (currently) 20%.