Flexible Photonics with High Contrast Metastructures
- Author(s): Zhu, Li
- Advisor(s): Chang-Hasnain, Constance J
- et al.
Light manipulation on a flexible, conformable, wearable surface with functions of light emission, detection and processing is the next frontier for many applications, including ubiquitous environment-awareness sensors for bridge, buildings, airplanes and robots; wearable health monitoring devices for public health; active camouflage; wearable displays and visual arts for commercial products; systems on a foil. However, the rigidness of the conventional photonic devices and systems limits their use in the flexible photonics application.
Despite the efforts that facilitate the flexible devices based on the organic materials, the performance of the devices are still compromised comparing with the devices made of the semiconductors. The transfer printing method provides an alternative paradigm in implementing the flexible photonic devices, by transferring the devices made of semiconductors on to the flexible substrates. However, many new challenges are arisen to incorporate the conventional photonic devices in the flexible platform, including thermal management, optical interconnect, etc.
The high contrast metastructure (HCM) is an emerging element for photonics, with its unique capability to achieve the light wave engineering in the sub-wavelength scale. It has abundant properties and design versatility. The HCM can be designed to be an ultra-thin broadband high reflectivity mirror, replacing the conventional DBR reflector with a superior performance. It can also be configured as a mirrorless resonator to achieve high quality factor resonance with convenient free space coupling.
This dissertation is devoted to explore the physics of the HCM in the near-wavelength regime, especially for its unique property in diffraction order enhancement and coupling. We present the new optical phenomena in the dual order diffraction regime and utilize this anomalous diffraction for making the first artificial chameleon skin. We also leverage on the ultra-thin thickness of the HCM reflector to significantly improve the thermal conductance for a heterogeneously integrated vertical cavity surface emitting laser (VCSEL). Through this effort, we demonstrate the first flexible VCSEL operating at the silicon transparent wavelength. Based on the HCM and external photonic structure coupling, we also demonstrate a variety devices for the efficient photonic integration on the flexible platform.