Power/Performance Bits: July 8

In an advance that could one day enable the miniaturization of laser systems, researchers at the University of Texas at Austin and the Technical University of Munich have developed a new nonlinear metasurface, or meta mirror.

The researchers call their invention a “nonlinear mirror,” which they believe could help advance nonlinear laser systems that are used for chemical sensing, explosives detection, and biomedical research, among other potential applications.

The metamaterials were created with nonlinear optical response a million times as strong as traditional nonlinear materials and demonstrated frequency conversion in films 100 times as thin as human hair using light intensity comparable with that of a laser pointer.

Nonlinear optical effects are commonly used to generate new light frequencies, perform laser diagnostics and advance quantum computing. Due to the small extent of optical nonlinearity in naturally occurring materials, high light intensities and long propagation distances in nonlinear crystals are typically required to produce detectable nonlinear optical effects.

The research team has created thin-film nonlinear metamaterials with optical response many orders of magnitude larger than that of traditional nonlinear materials. They demonstrated this functionality by realizing a 400-nm-thick nonlinear mirror that reflects radiation at twice the input light frequency. For the given input intensity and structure thickness, the new nonlinear metamaterial produces approximately 1 million times larger frequency-doubled output, compared with similar structures based on conventional materials.

The work is believed to open a new paradigm in nonlinear optics by exploiting the unique combination of exotic wave interaction in metamaterials and of quantum engineering in semiconductors and unveiling a pathway towards the development of ultrathin, highly nonlinear optical elements for efficient frequency conversion that will operate without stringent phase-matching constraints of bulk nonlinear crystals.