Extreme Wavefront Control Lab

MagAO-X integration and testing continues apace, with Jared shaving microseconds off the loop latency, Kyle working on making the world’s flattest DM, and Alex H. identifying holes in our hardware that were made in the wrong place. The rest of us are fighting with hardware more indirectly, getting our simulations to converge or our embarrassingly parallel jobs to be more than a (parallel) embarrassment.

Lauren Schatz, pyramid wavefront sensing person extraordinaire, has recently been the victim of delegation by the P.I. Her task? Arranging the weekly group meeting. In retaliation, she decided the venue would be outdoors. On a 95ºF (35ºC) day.

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Our recent meeting was graced by a special guest: incoming graduate student (and NSF Graduate Fellow) Logan Pearce! She talked to us about research she’s been doing with Adam Kraus at University of Texas at Austin using data from the Gaia mission. This fall she plans to join the XWCL and MagAO-X team here at The University of Arizona. Welcome, Logan!

Several of us (but not this author) will be at AO4ELT6 next week, and everyone is diligently working on their posters and talks. If you’re there, keep an eye out for our group:

• Monday, June 10
  • Development of the Three Sided Pyramid Wavefront Sensor — Lauren Schatz (poster)
  • Focal plane wavefront sensing and control with a vAPP coronagraph on MagAO-X using holographic modal wavefront sensing and linear dark field control — Kelsey Miller (poster)
• Tuesday, June 11
  • Characterization and closed-loop laboratory testing of deformable mirrors for the MagAO-X project — Kyle van Gorkom (talk @ 9:40 AM)
  • Real-time estimation of NCPA and exoplanet detection in the face of wavefront measurement error in extreme-AO coronagraphs — Alexander Rodack (talk @ 5:40 PM)
  • Imaging habitable planets in optical/NIR with large ground-based telescopes: WFS/C challenges, opportunities and R&D activities — Olivier Guyon (poster)
• Thursday, June 13
  • The Current Optical and Mechanical Design for the GMT High-Contrast Exoplanet Instrument GMagAO-X — Laird Close (poster)
• Friday, June 14
  • From MagAO-X to GMagAO-X: extreme-AO performance demonstration and science case for the GMT — Jared Males (talk @ 10:00 AM)

In recognition of recent climatic developments in Tucson, Arizona, your author has selected this as the song of the day:

The school year has wrapped up and we’re about to head into summer. Usually we’re excited we survived the year at all, but this time we are celebrating the XWCL undergraduates graduating and completing their bachelor’s degrees! Chris, Maggie, and Madison have worked with us for the past couple years assisting on MagAO-X.

Chris joined us in 2016 as a computer science undergrad. He started working with Katie doing data reduction. Jared then poached him away to work a lot in the lab doing mostly hardware coding and is the original Basler camera whisperer. He is going to stick around with us for a few weeks to wrangle some more hardware control programming before journeying off to a real job with Fast Enterprises.

Maggie joined us in 2017 as an optical sciences and engineering undergrad. She’s worked primarily with Laird on MagAO-X optomechanical design and alignment. She came along with us to SPIE last year and is part inventor with Laird on the optomechanical mount patent. She will be suffering sticking around with us this fall at UA for a PhD in optical sciences, where she will also be an NSF GRFP recipient. She is off to a summer internship in Baltimore at STScI working on HiCAT.

Madison joined us in 2018 as an optical sciences and engineering undergrad. She worked with us part time last summer to help Lauren with the MagAO-X pyramid wfs alignment and joined us for the past school year doing quantum efficiency testing for a light source. She will be partially suffering sticking around this fall at UA for a MS in optical sciences. She is off to a summer internship in Boston at MIT Lincoln Laboratory.

The MagAO-X PI has expressed an interest in the return of having a song with the blog posts. With the help of Joseph, we have a graduation-themed song for EACH of the undergrads:

For Chris, we have “Shut Up and Let Me Go” by the Ting Tings:

For Maggie, we have “Move On Up” by Curtis Mayfield:

For Madison, we have “Take Yourself With You” by Rose Linor Dougall:

Also, as tradition with the blog, here are quotes. The MagAO-X PI has some parting words for the graduating undergrads:

Jared: You’re here until you die*
*Source: “Look Down (Prisoners)” from Les Miserables

Congratulations again to the undergrads, XWCL is super proud of all the hard work you’ve done! Here’s to a fun and productive summer for everyone!

* with two DMs! But not at the same time…yet.

Late last week, after painstakingly recabling and aligning the BMC 2K following its relocation to the MagAO-X instrument, we closed the loop at 3.6kHz with 2040 actuators. See Jared’s video below:

What exactly are we looking at in this video?

On the far left is the image from our pyramid wavefront sensor. It’s tricky to interpret, but the four pupil images are a bit (but not exactly) like a 2-axis knife-edge test, with the key difference that aberrant rays are refracted into the different pupil images rather than simply blocked or passed. Through the magic of linear algebra (and lots of calibration), each frame from the wavefront sensor is converted into a map of voltages to apply to the DM to cancel this wavefront error.

The DM commands can be found along the bottom row of windows in the video. It’s split across multiple channels, but the important one is the image on the far right: each pixel is a command we’re sending to an individual actuator on the DM. With the loop open, we’re just creating simulated atmospheric turbulence. With the loop closed, it’s the same simulated turbulence plus the correction computed from the wavefront sensor.

And, finally, on the upper right is the “science” PSF, doing its thing. (That last image on the desktop—the pixelated one in the top middle—is the command sent to the ALPAO DM, but it’s not doing anything here other than holding a flat shape.)

Before we could close the loop, the 2K had to be aligned, which isn’t a trivial task when you’ve just dropped it into the middle of a rather complicated optical system and expect the beam to be centered on the DM to better than one actuator (which have a pitch of 400 microns). Enter Laird and Alex, experts on all things alignment. To aid in their efforts, we placed a pattern on the DM that could be seen both on the wavefront sensor and by eye in the beam reflected by the DM.

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This isn’t the first time we’ve closed the loop on MagAO-X. A month ago, we closed the loop on the low-order ALPAO DM-97 (the woofer). We have video evidence of that too:

And finally, to procrastinate studying for finals a few moments more, here’s my half-micron (peak to valley) entry into the ongoing MagAO-X logo contest, imprinted on the 2K and measured on our Zygo interferometer: