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- Calibrate the correction function between the DM and the HASO. This step is needed if the HASO has been used in a different location, or the laser beam pointing has change significantly, i.e. if you realigned the WFS in the previous section. You can also do the calibration if you think previous calibration is not accurate enough.
- Go to AO calib tab, and click start. You need to stop running in the AO tab to do the calibration.
- Wait until it finishes. This may take a while depending on the laser rep-rate and number of shots summed in each data point.
- Flatten the wavefront using closed loop.
- Go back to the AO tab.
- Save the current position of the pistons if you think it may be useful. It should remain unchanged from before calibration.
- In AO tab, make sure that correction mode is set to "Auto." Use "costum" only if you want to correct to a reference wavefront, i.e. in tunnel. The saved settings are generally good without change.
- However, if desired, you can change the loop settings in the loop configurator. There you can set the desired maximum number of Zernike orders. For 20-shot average on the fully amplified beam, recommended setting is between 10 – 15. If you want to try higher orders, select Auto in the security check to avoid pistons are driven too far. Use finite number of closed loop correction (normally between 5 – 15).
- Optionally you could open the WFS window and chose "PSF" to observe the strehl ratio during the loop.
- Click the run arrow in the main menu, then select Close loop on. It will run for the number of loops that you have set and stop. Usually the wavefront can be flatten to 50nm RMS and difficult to go down further.
- Check the Inj Far or other far field imaging after the DM during the loop to ensure that the loop works.
- Save the piston positions after the loop.
- Depending on the results, recalibrate the pistons after the loop and repeat the loop to further optimize the wavefront if needed. Typically the strehl ration will exceed 0.9 after 1 loop run.
Close the program. Wait until the following message box shows up. All settings will be save to the current session.
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