4.23.09

The parts that I need to install the SLM haven't arrived yet, but I've started reconfiguring my setup to accommodate it anyway. In the mean time, I'm using the new WFS to make some basic measurements of the laser source by removing as many elements as possible. I have no idea how the lens on the end of the diode affects the wavefront, so I'm trying to collimate the beam as much as possible adjusting it and passing the beam through a relay telescope (to expand the beam) only.

Assuming I get my order, I think a reasonable timeline for all this is to have the SLM/software installed by the end of next week and putting out some basic commands. Hopefully another week will be enough to get some reasonably realistic dynamic disturbances going, but its condition is unknown, so this might be wishful thinking.

In addition:

1. The full rank phase reconstructor I wrote appears to work reasonably well for spot measurements of the phase. Even though I know the pixel size (in m) and the focal length of each lenselet, I haven't entered it all in to get actual units yet, but that's a minor problem.

2. Using this phase reconstructor, I've pretty much confirmed (finally) that the mirror surface displacement (and hence wavefront phase) is linearly proportional to the square of the voltage commands. I did this by comparing the maximum phase value to a constant voltage command. Although not perfect, the curve is more linear than anything else. I'd like to try this again using just the center actuator when the system is reconfigured.

3. The new WFS is much faster, which means less bullshitting on the internet and more experiments. There is much less noise (since there's no crack running through the lens), so single frame measurements seem to be good enough. Combined with the increased frame rate, the control loop runs at 2-3 Hz. Playing around with the MATLAB frames per trigger setting, I might even be able to characterize the full response of the mirror (rise time, etc), since some transient response is definitely visible on the target camera. The input/output values in that case would be in terms of modal commands/projections I guess.

As the system moves to its final form, I'm beginning to shift away from the optics nonsense and get more into the adaptive control, which is really what all this is about anyway. Unfortunately, with that comes the absolute shit storm of material I have to review. Several of the books I'd like to review have Bible-like density, so there's a lot of reading to be done over the next few weeks.