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Maintained by WW

Adaptive Optics Development

The Adaptive Optics Laboratory at the IfA, led by Mark Chun and Christoph Baranec, develop innovative technologies and systems that counteract the image-blurring effect of Earth's atmosphere.

The ‘imaka project, led by Chun, is working toward extremely large corrected fields of view at visible and near-infrared wavelengths. By correcting for the atmosphere just close to the telescope, the team has demonstrated corrected fields of view larger than previously thought possible.

Robo-AO, led by Baranec, is a fully robotic system that can observe hundreds of objects per night at near Hubble Space Telescope resolution.

Don Hall is developing a new photon-counting near-infrared detectors that are used in several adaptive optics systems: Robo-AO, the pyramid wavefront sensor for Keck, and with SCExAO at Subaru.

See also  Adaptive Optics at the Institute for Astronomy

  

Robo-AO laser at the UH 2.2m telescope (credit Sean Goebel)

Infrared Sensor Arrays

The infrared sensor array development program, led by IfA-Hilo astronomers Don Hall and Klaus Hodapp, teams with commercial vendors to develop and optimize near-infrared (0.8μm - 5.5μm) mercury cadmium telluride (HgCdTe) arrays for both ground-based and space-based astronomy. The vendors do not have the means of evaluating their performance under demanding astronomical conditions, so the UH group characterizes these arrays, both in the laboratory and at the telescope, and then identifies ways in which they could be modified to improve their astronomical performance. Once UH and the vendor agree on the design and architecture of a new astronomy-optimized array, UH submits a proposal to either NSF or NASA and then both oversees the vendor’s development of the new array and characterizes its properties for astronomical observations.

The IfA teamed with Teledyne Imaging Sensors to develop the widely-used "HAWAII" series of arrays, where "HAWAII" stands for "HgCdTe Wide Area Infrared Imager". The 2048 x 2048 H2RG and the 4096 x 4096 H4RG are now in use at almost all major ground-based observatories, as well as many space missions including JWST, Euclid and WFIRST.

For observations at the lowest light levels, the "HAWAII" arrays are limited by "read noise" generated within the chips. The IfA group is now teamed with another vendor, Leonardo MW Ltd, to use linear-mode avalanche photodiode (LmAPD) technology to produce ultra-low read-noise sensors. Under the right circumstances, this technique can boost the signal to noise ratio by a factor of up to 100. The SAPHIRA arrays are now the sensor of choice for adaptive optics wave-front sensing and IfA is funded by NASA to develop large format LmAPD arrays for future space astronomy missions.

 

A "HAWAII" 4096 x 4096 pixel chip (on the right), reflects
an image of the computer chip that is used to control it.

CryoNIRSP Solar Spectropolarimeter

CryoNIRSP, one of the five first-light instruments for the Daniel K Inouye Solar Telescope (DKIST) on the summit of Mt Haleakala, is currently under construction at the IfA facilities on the island of Maui. It is the only cryogenic infrared spectropolarimeter of its kind. Between wavelengths of 1-5 micron it provides high resolution and high sensitivity spectropolarimetric measurements of the Sun's disk and corona. The 2-ton instrument will sit on the rotating coude floor of DKIST, where it will provide astronomers with their first routine measurements of the Sun's, thus-far, mostly invisible coronal magnetic field. Jeff Kuhn (IfA/Maui) is the PI with Dr Andre Fehlmann the instrument scientist and Dr. Isabelle Scholl the project manager.

The lifting assembly in the Maui Advanced Technology Research laboratories holding the outer shell of the cryostat  in the background. The cold-optical bench structure before radiation shielding was installed is being worked on in the foreground.

 

 

IRTF Spectrograph

Mike Connelley is designing a low resolution prism spectrograph as the next facility instrument for the IRTF.  Optimized for near-Earth asteroid characterization and transient follow-up, it has very high throughput, a 8"x8" field of view with a image slicer IFU.  It will also have simultaneous and continuous coverage from the 350 nm to 4 microns to observe a broad range of minerals on asteroids.  

 

 

 

 

 

 

 

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