Nanoscale Poling and Structuring in Nonlinear Optical Materials
Phil Himmer, Montana State University Awarded from 2015
In scientific and engineering applications involving laser communications or sensing, nonlinear optical materials such as lithium niobate (LN) play a critical role, as they enable wavelength conversion and amplification of optical signals. Recent innovations (including those of collaborator AdvR, Inc.) such as periodic poling for quasi-phase matching (QPM) and structuring to produce ridge waveguides are expected to significantly improve the efficiency and power handling of these devices. Currently, typical domain sizes in periodically poled LN range from several microns to millimeters; reducing the size of these domains would enable higher efficiencies and new applications. However, traditional methods of poling these materials are incapable of scaling down to these sizes. In this proposed work, we plan to investigate the structuring and poling of LN (congruent and magnesium oxide doped) on micron and sub-micron size scales using nanofabrication methods. This includes: (1) optimization of electron-beam lithography and etch/liftoff techniques to produce sub-micron size masks on LN; (2) highly selective poling processes to transfer the nanoscale mask patterns into the LN; and (3) optical and electrical techniques for characterization of the poled LN with sub-micron size domains. Combined with confinement provided by thin device layer LN-on-insulator wafers, nanoscale masking and poling techniques will enable the realization of new nonlinear optical devices. This, in turn, provides a development platform for high-efficiency nonlinear optical devices with applications including tunable IR laser sources for atmospheric science, entangled photon pair generation for secure communications, and high-efficiency wavelength upconverters (IR to visible) for low-light detection.
Electrical and Computer Engineering
Montana State University
Bozeman, MT 59717