NRL Improves Optical Efficiency in Nanophotonic Devices

Ultralow-loss polaritons in isotopically pure boron nitride. (U.S. Naval Research Laboratory)

Image shows directly measured polaritons propagating through a flake of Hexagonal boron nitride (hBN). This material has been identified as an ideal substrate for two-dimensional materials research while also recently being demonstrated as an exciting optical material for infrared nanophotonics. (U.S. Naval Research Laboratory)

March 26, 2018 | Source: U.S. Naval Research Laboratory, nrl.navy.mil, 4 Jan 2018, Daniel Parry

A team of physicists, headed by the U.S. Naval Research Laboratory (NRL), have demonstrated the means to improve the optical loss characteristics and transmission efficiency of hexagonal boron nitride devices, enabling very small lasers and nanoscale optics.

“The applications for this research are considerably broad,” said Dr. Alexander J. Giles, research physicist, NRL Electronics Science and Technology Division. “By confining light to very small dimensions, nanophotonic devices have direct applications for use in ultra-high resolution microscopes, solar energy harvesting, optical computing and targeted medical therapies.”

Hexagonal boron nitride (hBN) forms an atomically thin lattice consisting of boron and nitrogen atoms. This material has recently been demonstrated as an exciting optical material for infrared nanophotonics and is considered an ‘ideal substrate’ for two-dimensional materials.

While previous work demonstrated that natural hBN supports deeply sub-diffractional hyperbolic phonon polaritons desired for applications, such as, sub-diffractional optical imaging (so-called ‘hyperlensing’), energy conversion, chemical sensing, and quantum nanophotonics, limited transmission efficiencies continue to persist.

"We have demonstrated that the inherent efficiency limitations of nanophotonics can be overcome through the careful engineering of isotopes in polar semiconductors and dielectric materials,” Giles said