285 nm-Laser (S-MOT)

The 285 nm Laser consists of a two-stage frequency doubled, raman-fiber-amplifier MOPA. The raman-fiber-amplifier is seeded by a diode laser.

• Laser-Diode current: .. mA
• Seed power (is displayed in the FLPM RMU CCT 1.1.0.0 program): ~ 20 mW

• Enable main-switch. Set key to standby.
• Wait for the LED to change the color from orange to green to orange (~15 seconds after turning on). Turn the key now.
• Start the program FLPM RMU CCT 1.1.0.0 and select the checkbox of Laser Enable.
• The Power Setpoint must stay at 0.500 W
  • Optimize fiber coupling to Iodine Spectroscopy. Transfer-efficiency > 70%
• Change Power Setpoint for 285nm SHG operation
  • 2 - 2.500 W for 100-150 mW directly after 285 nm SHG.
  • Do not exceed much more than 3.5 W

• Start DigiLock-Module Server and connect to S-MOT-Laser
  • Push Scan on and AutoLock
  • Change the Offset Value to 0 V
  • Change the frequency with the piezo on the toptica rack electronics to be close to the iodine resonance (check with wavemeter)
  • Change the Setpoint (under AutoLock) to be in the middle of the error signal. Check, if the crosshair snaps to the slope.
  • Move the crosshair to the second slope, rightclick on press PID: Lock to Slop.

The 285nm SHG was build by Jan Friebe and is described in his diplomathesis.

• Outputpower after cube to 285 nm-SHG: ~ 1.2 W @ 2.5 W
• Operationpower: < @ 3 W
• Max outpupower: ??? W @ ??? W

• Infront fiber: ~ 38 mW @ 0.500 W
• After fiber: ~ 29 mW @ 0.500 W (= 400 mV @ 0.500 W) [efficiency ~ 70 %]

• Infront fiber: ~ 220 mW @ 2.500 W
• After fiber: ~ 160 mW @ 2.500 W (= 2 V @ 2.500 W) [efficiency ~ 70 %]

• Outputpower: ~ … mW @ 2.000 W
• Outputpower: ~ 100 mW @ 2.500 W
• Power for photodiode: ~ … müW
• Stabilized power (infront AOM): 80 mW

• Power infront the AOM in … order: 80 mW
• Power behind the AOM: 43 mW @ 2.500 W (efficiency ~ 50 %)

• Power for the Zeaman-slower: … mW

• Power behind the mystical mirrow: … mW