Sandia Researchers Develop Mirage Software that Makes Optical Engineering Relatively Easy

An innovative software now allows users to create science-fiction-like materials with the same level of efficiency that designs draft-building plans.

Researchers at Sandia National Laboratories have developed the world’s first inverse-design software specifically for optical metamaterials, which means users can begin by elucidating the result they require, while the software fills in the steps to reach there. The contemporary design technique takes the uncertainty from engineering as-yet hypothetical technologies, such as high-performance, ultra-compact cameras as well as cloaking armor that makes it impossible to detect wearers, rendering them invisible.

In its research and development programs, Sandia National Laboratories employs the design aid, known as Mirage, and even introduced a test version to choose collaborators in the previous year. Currently, a license can be availed by investigators working on government metamaterial projects without any cost.

For more than 10 years, artificial, optical metamaterials have been hyped for their potential to exploit light in unusual ways. Theoretically, interstellar telescopes and satellite imaging could be radically smaller with metamaterial lenses being a hundred times thinner compared to traditional counterparts. Or, someday, the technology may lead to unique cloaking materials that deflect light around them, making objects completely invisible. For materials that would be needed for such technologies, mirage streamlines and automates the design process.

Mirage takes guesswork out of design

So far, the domain of optical metamaterials has found it difficult to deliver on all its apparent promise of redefining optics. For engineers, one major complication was that metamaterials are composed of very small building blocks, known as meta-atoms, which can be engineered in many different variations. Collectively, a specific shape may bend light. If the spacing, size, shape, or the material is changed, then that may either diminish the effect or amplify it, or lead to something completely different, for example, the light may be twisted in one direction or another or its color or intensity may be changed.

Predicting what the bulk ‘homogenized’ properties will be has been very hard to determine until now.

Mike Fiddy, Program Manager, Defense Advanced Research Projects Agency.

The development of the software was funded by the Defense Advanced Research Projects Agency (DARPA).

While there are other kinds of software that are capable of simulating what meta-atoms will actually do to light, that merely enables scientists to use their intuition to test different kinds of designs until they laboriously work out or stumble upon the behavior they require.

In spite of the challenge, a few scientists were successfully able to develop imaginative metamaterial devices. Sandia National Laboratories developed a unique device that changes heat to electricity, possibly for engines that are more fuel efficient, and a light-mixing technology that may result in a novel, changeable, multicolored light source, which may speed up numerous kinds of studies ranging from biomedicine to archeology.

However, in general, the metamaterial enterprise required a boost, stated Sandia researcher Ihab El-Kady.

We cannot possibly solve this problem by trial and error. Instead, we could do the opposite. We could say: ‘ere is the behavior I want. Now tell me what the metamaterial looks like.’

Ihab El-Kady, Scientist, Sandia National Laboratories.

The Mirage was conceived by El-Kady.

This inverse-design method was not used by any tool. Hence, El-Kady along with his group at Sandia’s National Security Photonics Center developed one such tool.

User-friendly instructions to exploit 100-plus templates

Mirage allows users to begin by telling it the optical trait they need—for instance, how their metamaterial has to interact with light—and their preliminary materials.  Moreover, the designs generated by Mirage correspond with criteria from a library of over 100 templates. Alternatively, users can create their own specific designs, and these will be checked by the program for any kind of errors.

“A more systematic approach for designing metamaterials should greatly accelerate their adoption in various application areas,” removing more oft-used and intuition-based methods, stated Fiddy.

At its 60^th Anniversary Symposium held in Fort Washington, Maryland, DARPA featured Mirage as a leading technology, demonstrating its far-reaching applications.

Mirage is an all-in-one tool. Not only does it tell you what the metamaterial looks like, it allows you to explore various configurations, simulate the system, validate the chosen behavior, visualize its response and optimize its functionality within your fabrication constraints.

Ihab El-Kady, Scientist, Sandia National Laboratories.

Software refines powerful ideas

Besides that, Mirage is also useful since it contains algorithms that aid investigators to achieve the most optimum performance from their inventions, informed Igal Brener, Sandia senior scientist who applies the novel software in his metamaterial studies.

Earlier, Brener’s group developed a material that can combine two lasers to generate 11 colors simultaneously, including ultraviolet and infrared light. This technology could even be advanced into tunable lasers that substitute single-color equivalents. However, some of those colors are very dim and hence are not useful. Therefore, Brener is looking for ways to brighten the output. Brener has also utilized other software packages like simple optimization algorithms, but to utilize more sophisticated algorithms he needs to complement those packages with his own unique coding. But that is not so in the case of Mirage.

Optimization techniques come in many different flavors. Mirage is the only software package I know of that has the complex optimization techniques I need built in.

Igal Brener, Senior Scientist, Sandia National Laboratories.

If the first launch proves to be successful, Sandia National Laboratories will plan to develop another version of Mirage, tentatively known as Mirage Elite, that would introduce a boost in optimization by automatically transforming meta-atoms into outlandish and strange shapes in the quest for undiscovered behaviors.

Watch a preview of Mirage, software developed by Sandia to make optical engineering (relatively) easy. The cubes in the video are blueprints of meta-atoms, nanosized building blocks that give metamaterials their distinctive, unusual properties valued for new technologies. (Video credit: Sandia National Laboratories)