Times they are a changin'

Here's a dandy chart showing the decrease in frame rate as the WFS image size is increased. Each sub-aperture is around 22 px across, and each pixel is around 6 um, so that gives you an idea of the beam size necessary. I also varied the shutter speed, but this should obviously be set to the minimum value necessary to see the centroids.



Aligning the beam is turning out to be problematic because the divergence is significant as the beam size shrinks. The good news is that a windfall in our equipment budget means I'm finally getting a HeNe laser like I always wanted. expanding it is slightly more involved than with the diode laser I'm using now, but I should be able to clean it up using a spatial filter and get a pretty nice spot.

As a matter of fact, we also ordered a new DM to use in place of the retarded SLM I've struggled with. The new DM contains around 60 actuators compared to the 31 in the current model. It might seem odd to use the higher density DM as a disturbance generator, but in RL atmospheric turbulence is always going to generate higher (spatial) frequency distortion than can be corrected with a finite actuator DM.

This basically means that all the active components of my experiment are going to be repaired/replaced in the next few weeks. I really really hope that's it because frankly i'm tired of dealing with all this optics shit.