Commentary

Extreme Engineering Key to Adaptive Optics Advances

Throughout Lawrence Livermore’s 62-year history, one of its enduring competitive strengths has been its ability to rapidly mobilize multidisciplinary teams to respond to an exceptionally wide variety of customer needs. This concept is particularly evident within the 1,500-member Engineering Directorate. Livermore engineers—computational, electrical, mechanical, chemical, and optical—play leading roles in many Laboratory projects, working alongside physicists, computer scientists, chemists, geologists, and other researchers.

An outstanding example of teamwork was the nearly decade-long effort to design and build the Gemini Planet Imager (GPI), the first astronomical instrument for directly imaging and analyzing planets outside our solar system. Attached to the Gemini South telescope in Chile, GPI uses a technology called adaptive optics to compensate in real time for the twinkling of starlight caused by Earth’s turbulent atmosphere and thereby produce much clearer images of stars and planets.

GPI’s adaptive optics system serves as a showcase for Livermore engineers’ prowess in pushing the limits of technology, as described in the article Giant Steps for Adaptive Optics. The GPI system produces the clearest images of extrasolar planets (exoplanets) ever recorded and performs about 70 times more quickly than existing instruments in detecting exoplanets many light-years away. The instrument, currently in its final shakedown phase, is operating superbly. Over the next three years, Gemini imaging results are expected to strengthen scientific understanding of how planetary systems form and evolve, how planets’ orbits change, and what comprises their atmospheres.

To meet GPI’s stringent operational requirements, a Livermore team of optical, computational, and electrical engineers, working closely with astrophysicists and astronomers, developed several technologies that exploit the power of adaptive optics to search for exoplanets. The engineers devised a remarkably agile system that measures the light passing through the Gemini South telescope 1,000 times per second at nearly 2,000 control points in the telescope’s 8-meter aperture. Every thousandth of a second, the system corrects for distortions by adjusting the shapes of two deformable mirrors. The one designed for fine focusing measures only 2 centimeters on a side, yet it employs 4,096 tiny microelectromechanical actuators. Another Livermore advance, a self-optimizing computer system, controls the actuators with computationally efficient algorithms that are continually determining the ideal position for each actuator.

Building on the expertise gained from developing GPI, the Laboratory is bringing adaptive optics technology for visible light to the world of x-ray optics. If adaptive optics systems could correct common distortions in x-ray beams, Department of Energy high-energy research centers could reach their theoretical limits and achieve improved resolution to advance research in physics, chemistry, and biology. Working with industry, we have designed and built an x-ray deformable mirror that will be a key component of an adaptive x-ray optics system. We are testing this mirror along with new x-ray beam diagnostics at Lawrence Berkeley National Laboratory’s Advanced Light Source.

Our successful engineering accomplishments in adaptive optics, as with so many other research projects, serve as a compelling inducement to attract talented scientists and engineers to Livermore. For example, under our tutelage, two graduate students from the University of California are working on advanced adaptive optics algorithms.

In addition to the feature article, this issue of Science & Technology Review highlights three important initiatives in which engineers have substantial roles. The first article, Mapping Networks for Cyberdefense, describes how computational engineers helped develop a new software tool for enhanced cybersecurity. The second, Foams Help Heal a Deadly Affliction, details how chemical, materials, and computational engineers have combined advanced materials development and computational analysis into a new approach for treating brain aneurysms. Finally, in Additive Manufacturing Reshapes Foam Design, we report on improved cushions to protect nuclear weapons components, thanks to novel additive manufacturing techniques that create new kinds of exquisitely engineered materials.

The enduring success of Livermore engineers working comfortably with researchers from a host of disciplines, institutions, and industrial partners illustrates the creative power of engineering innovation. With these most recent advances in adaptive optics, we have again demonstrated how engineering enables program success and ensures the Laboratory’s continuing vitality.

In November 2014, an international team of scientists begins a three-year campaign using GPI to discover and characterize giant exoplanets. We look forward to seeing the latest results of pushing engineering to the extreme.