M. Todd, C. Compton
We started setting up the Access CO2 laser in the optics lab, and after confirming that the beam coming from the aperature has not changed since previous tests, we have begun installing optics to test a setup we are imagining for CHETA.
Figure 1 is the proposed setup to test the QPD path. The ITM in this setup will really just be a screen or block, and we may do some razor-blade profiles of it. The QPD should be at the same Gouy phase as the "ITM", and this model adheres to that. So far, we have installed three of the steering mirrors and encorporated their measured distances (aligned to the optics grid) to this model, as seen in Figure 2.
Here are the beam parameters at the relevant points in the model, which may be confirmed with profiles.
q at Laser.fr.o from BeamTrace:
+-----------+-------------------------------+----------+-----------+----------+------------------+-----------------------+
| direction | q [m] | w [m] | RoC [m] | w0 [m] | Accum Gouy [deg] | Dist. form source [m] |
+-----------+-------------------------------+----------+-----------+----------+------------------+-----------------------+
| x | -1.140000e-01 + 4.268000e-01j | 1.24e-03 | -1.71e+00 | 1.20e-03 | 0.00 | 0.000 |
| y | -1.140000e-01 + 4.268000e-01j | 1.24e-03 | -1.71e+00 | 1.20e-03 | 0.00 | 0.000 |
+-----------+-------------------------------+----------+-----------+----------+------------------+-----------------------+
q at QPDStop.fr.i from BeamTrace:
+-----------+-------------------------------+----------+-----------+----------+------------------+-----------------------+
| direction | q [m] | w [m] | RoC [m] | w0 [m] | Accum Gouy [deg] | Dist. form source [m] |
+-----------+-------------------------------+----------+-----------+----------+------------------+-----------------------+
| x | -1.723144e-01 + 4.141798e-02j | 1.60e-03 | -1.82e-01 | 3.74e-04 | 237.00 | 3.273 |
| y | -1.720586e-01 + 4.111144e-02j | 1.60e-03 | -1.82e-01 | 3.72e-04 | 237.02 | 3.273 |
+-----------+-------------------------------+----------+-----------+----------+------------------+-----------------------+
q at ITMStop.fr.i from BeamTrace:
+-----------+------------------------------+----------+----------+----------+------------------+-----------------------+
| direction | q [m] | w [m] | RoC [m] | w0 [m] | Accum Gouy [deg] | Dist. form source [m] |
+-----------+------------------------------+----------+----------+----------+------------------+-----------------------+
| x | 1.451712e+00 + 2.808360e-01j | 5.13e-03 | 1.51e+00 | 9.73e-04 | 237.66 | 3.699 |
| y | 1.453071e+00 + 2.808360e-01j | 5.13e-03 | 1.51e+00 | 9.73e-04 | 237.67 | 3.699 |
+-----------+------------------------------+----------+----------+----------+------------------+-----------------------+
