Wataru Nakagawa, Ph.D. - US grants

ECCS - 1002058
Wataru Nakagawa
Montana State University
Hybrid Micro/Nano-Optical Devices for High-Fidelity Imaging

ABSTRACT

The objective of this research is to develop next-generation optical micro-electromechanical systems (MEMS) through the use of nanostructured surfaces, leveraging their underlying compatibility to realize multifunctional hybrid micro/nano-optical devices. The result will be MEMS-based systems capable of optical performance commensurate with bulk optics, leading to new fully miniaturized high-fidelity optical imaging systems.

Intellectual merit: Optical nanostructures have emerged as a viable alternative to implement high-reflectivity and anti-reflection coatings as well as polarization control elements. A desirable characteristic of these devices is that the required optical properties can be engineered through the nanoscale structure, freeing the choice of materials (e.g. for manufacturability or compatibility). In this project, nanostructured devices using MEMS-compatible materials and manufacturing processes will be developed and integrated with a MEMS device. These multifunctional hybrid devices will be optimized for specific target applications in compact high-resolution imaging systems, and validated in applications-oriented optical microsystems.

Broader impacts: The synthesis of two rapidly advancing areas of optical technology - MEMS and nanostructures - will enable the development of high-performance, miniaturized, multifunctional optical devices. Such devices have potential applications ranging from medical imaging and environmental monitoring to consumer electronics such as cameras and display systems. This work will also offer a wealth of opportunities for the education and training of participating students in engineering research and systems development, and will include efforts to encourage undergraduate and pre-collegiate students to pursue education and careers in science and technology fields.

This Research Experiences for Undergraduates (REU) Site program, hosted by the Electrical and Computer Engineering (ECE) Department at Montana State University (MSU), focusing on a central theme of "Observing Our World with Light and Sound", offers state-of-the-art, inter-disciplinary research experiences spanning the applications of this theme, as well as the development of enabling technologies, to diverse and talented cohorts of undergraduates from institutions with limited or no research opportunities. The ECE Department's diverse activities provide research opportunities catering to a wide spectrum of backgrounds and interests. Moreover, the research experience will open students' eyes to the nature of research, its role in understanding our world, and engineering solutions to the problems that we face. The interdisciplinary nature of the research efforts will also help the students to see how various academic disciplines come together to solve important problems.

The primary objectives of this REU site program are to provide each undergraduate participant with a ten-week intensive and immersive, research experience within a highly collegial environment of collaboration with faculty mentors and other students. The program focuses on the development of the technical skills and critical-thinking abilities of the participants and on their exposure to substantive, representative research activities aimed at developing and utilizing electromagnetic and sound-based observational tools and techniques for a diverse range of applications. In addition research will include a number of supporting technologies which enable the development of novel sensors such as micro-electro-mechanical systems (MEMS), lasers and photonics, nanotechnology, advanced image and signal processing, and reconfigurable computing. It will also emphasize development of the participants' technical communication abilities through several professional-development seminars and workshops and enhance their understanding of the ethical and societal context within which engineering research is performed. Industrial partners will be highlighted by including industrial researchers in the seminar series and including visits to local companies. The discoveries made during these collaborations will be communicated to the broader scientific community via publications and presentations.

Abstract ECCS-1710128

Title: GOALI Nanoscale Fabrication of Nonlinear Optical Devices

Non-technical description:
Nonlinear optical devices play a critical role in a wide range of optical systems, enabling signal amplification, wavelength/frequency conversion, and all-optical control or modulation of light. These devices have an immense range of applications, including communications, medical imaging, remote sensing and quantum information systems. One common approach to implement nonlinear optical devices is through quasi-phase-matching (QPM) or periodic poling. This method entails precise, small-scale modifications in the optical properties of nonlinear optical materials (poling) in order to dramatically improve their efficiency, and has revolutionized the field of nonlinear optics. The goal of this project is to develop new methods to reproducibly fabricate smaller poling domains in QPM nonlinear optical devices, potentially greatly enlarging the range of applications for these devices. Smaller poling domains would enable wavelength conversion devices capable of working with at different optical wavelengths, greatly enlarging the operating wavelength range in communications or medical imaging applications. Such devices would facilitate the detection of very weak optical signals at longer wavelengths and enhance the performance of remote sensing or quantum information systems. This work will be performed in collaboration with an industrial partner, AdvR Inc., under the framework of the Grant Opportunity for Academic Liaison with Industry (GOALI) program. This academic-industrial partnership will leverage the capabilities and resources of both partners to achieve the project goals. The associated education and outreach efforts will promote student participation, from underrepresented minority groups, in the Montana Apprenticeship Program. In addition, the GOALI collaboration will allow students to have strong research interactions in both academia and industry.

Technical description:
The PI proposes to develop nanoscale fabrication methods that will lead to the next generation of nonlinear optical devices. Optical waveguides using periodic poling have revolutionized nonlinear optics by providing significantly higher efficiency and enabling engineering of the optical properties of devices. Lithium niobate material (LN), especially doped with magnesium oxide (MgO:LN), has been frequently used due to its relatively strong nonlinear properties that lead to higher efficiency and power- handling capability. The basic goal of this project the process development to enable sub-micron scale poling and structuring of MgO:LN. Periodically poled nonlinear optical waveguides with nanoscale domains would facilitate parametric wavelength conversion with higher efficiency and with greater control over the operating wavelengths (e.g. operation in the infrared). Once the methods to produce nanoscale poling domains and to control structural features in MgO:LN have been established, further investigations to enhance the nonlinear performance of these devices will be pursued, such as dispersion engineering and wavelength-selective resonant cavities. The proposed work will enable the realization of a mirrorless optical parametric oscillator (OPO) that would enable high-efficiency nonlinear optical processes with relatively short interaction lengths and significant flexibility in operating wavelengths. Such OPOs would significantly broadened range of applications for nonlinear optical devices.