We investigate individual collagen fibrils using polarization SHG microscopy. It is found that polarization SHG is sensitive to changes in fibril structure caused by hydration, and changes in fibril out of plane orientation as a result of buckling.
We propose a novel Chand-Bali nano-antenna that uses a gradient-based optimization method to achieve polarization-independent operation in the infrared range, specifically at 10.6 μm. The optimized design allows for wide-angle reception. The nano-antenna is made up of two elliptical metallic resonators, one of which has an elliptic cut. It serves as the top layer of a metal-insulator-metal (MIM) structure, which allows for easy formation of thin insulator layers in the gap of the metallic resonators, creating an infrared energy harvester rectenna. The strong confinement of the electric field in the gap improves the performance of MIM rectifiers. Our simulations indicate that this design is well suited for energy harvesting and detection, and can be scaled to different wavelengths.
We present the use of an optical phase change material to create scalable and reconfigurable optical logic switches. We demonstrate that two logic operations can be achieved at a single wavelength using a single microdisk; while dual nanobeams in a Mach-Zehnder configuration could realize a resonant bistable crossbar switch. More complex logic functions can be obtained by introducing multiple stage cascaded microdisks or Mach-Zehner networks. This work suggests alternative switch configurations in silicon photonics.
A single-mode optical fiber coupler is demonstrated from ZBLAN fiber with a coupling ratio of 61%/39% at a wavelength of 2.7 $\mu$m. Single-modedness is evidenced from the absence of modal interference in the transmission spectrum. Coupling to the cross-port is limited by the onset of crystallization during the tapering process, which fosters signal loss through scattering.
Integrated optical phased arrays (OPAs), fabricated in advanced silicon-photonics platforms, enable manipulation and dynamic control of free-space light in a compact form factor, at low costs, and in a non-mechanical way. In this talk, I will highlight our work on developing OPA-based platforms, devices, and systems that enable chip-based solutions to high-impact problems in areas including augmented-reality displays, LiDAR sensing for autonomous vehicles, optical trapping for biophotonics, 3D printing, and trapped-ion quantum engineering.
