All pages in this lab

1. Laser Induced Fluorescence and Raman Scattering
2. Hologram Development Procedures
3. Laser Startup Instructions
4. Optics and the Spectrometer
5. Troubleshooting

Please be careful! We want this experiment to be safe and fun. We are relying on you to follow procedures and use good judgment. For instance, before you start, make sure the beam path is free of extraneous objects. Never move objects in or out of the beam while the laser is on. And be mindful whenever you manipulate reflective materials around the laser beam: It only takes one unfortunate reflection to cause a lifetime of damage.

To Turn on the Laser

1. Ask a staff member for a pair of Laser Vision protection goggles. You must wear goggles while the laser beam is on.
2. DO NOT TURN WATER ON FIRST !!! First PUSH and hold the water interlock box BUTTON while turning on the main water valve, located in the back left corner of the apparatus bench, turn main water valve CCW 90 degrees. The valve to the blue tank should be on with a Leave On sign labeled. Water should be flowing through the laser and out to the sink (located near the East wall in front of you as you face the laser). Make sure the water is flowing into the sink.
3. Turn on switch
   

   #28

   in the circuit breaker panel. This panel is located on the wall between the Rooms 286A and 286B inside room 286.(to the right of the laser). Steps 4-11 refer to controls on the Spectra-Physics 265 Exciter Laser Power Supply located under the laser:

4. Set the Meter Function switch to the 50 amp position.
5. Set the Current Control to about mid-range (around 5).
6. Set the Mode switch (to the right of the current control knob) to the left.
7. Set the field control knob to 5 for, ten (10) minutes, then to its maximum value (full clockwise).
8. Check that the "Water On" light and the three "Line" lights are on.
9. Switch on the line switch.
10. Wait 30 seconds for "Ready" light to be on.
11. Press the "Start" button. There should be an output beam from the laser and the "Ready" light should be off.
12. The output power of the laser can be tuned by adjusting the current knob on the power supply. You need at least 1 W of power to do the experiment (as measured on the front panel of the laser power supply meter). NOTE: the laser puts out ~ 1.4 watts of 514.5nm power. If you cannot attain that power level, see the staff.
13. Run the Laser for stable output power for 30 minutes before starting to user the laser.

Note: During calibration or any time that the laser is not in use, turn it off by flipping the "line" switch down. Turn it back on using steps 4 through 12.

To turn off the laser when you are done for the day

1. Turn off the 'line' switch on the laser power supply.
2. Turn off breaker \#28 in the circuit breaker panel.
3. Note You MUST turn off the main water IN-valve, CW 90 degrees, and then you can go home. The water will continue to run untill the Laser has cooled off. No overnight runs on this experiment. The water must be kept flowing until both inlet and outlet water pipes are the same temperature.

Gas Handling Procedures

Only adjust the gas if you have been trained to use these procedures by a staff member!

You will be releasing pure oxygen through the relief-valve, this is a volatile gas, please be sure that there are no open flames or smoldering embers nearby before you begin (Obviously this prohibits cigarette smoking).

The procedures reference 'Tank-Valves' and 'Outlet-Valve' refer to the "Gas Flow Diagram" near the rear of this write-up.

1. Close both tank-valves and outlet-valves.
2. Open the cell relief-valve. The pressurized contents of the cell should begin venting through the relief valve with a gentle hiss about 5 seconds in duration. Leave the relief-valve open.
3. On the tank of the gas with which you wish to fill the cell . . .
   1. Open the tank-valve and
   2. Open the outlet-valve
4. Allow the system to flush for 5 to 10 seconds.
5. Close the relief-valve
6. The cell should pressurize to about . . .
   1. 55 ± 5 PSI for O2
   2. 110 ± 10 PSI for N2
   3. If it does not, do not attempt to adjust the pressure. Instead, ask for assistance.
7. Close the tank-valve and the outlet-valve.

Gas Flow Diagram