Opto-Thermo-Mechanical Microsystems for Energy Conversion and High Precision Sensing

点击翻译按钮获取中文摘要

The general philosophy of my program is to harness recent progress from fundamental nanoscale science and translate them to new disruptive applied technologies. Following this philosophy, our specific goal for this proposal is to exploit recent progress from the fields of (1) nanoscale thermal transport and (2) optomechanics to create a novel class of opto-thermo-mechanical microsystems. The potential applications of these microsystems are divided in three sub-objectives: (1) direct conversion of heat to electricity, (2) high precision infrared and THz light detection, and (3) high precision vibration sensing. ******Our first objective is to create novel portable solutions for electricity generation from heat using the Near-Field Thermophotovoltaic (NFTPV) effect. The principle is to build modules in which energy from a heat source is radiated towards a specially tailored photovoltaic cell placed in its extreme proximity, typically <100 nm, for performance enhancement. We will develop high temperature micro-mechanical systems that will allow such sub-100 nm distance control and integrate them with photovoltaic cells. We aim to achieve the first demonstration of this technology which, at term, promises greater conversion efficiencies than existing thermoelectric generators. ******Our second objective is to enhance the detection limit of infrared (IR) and terahertz (THz) photodetectors using optomechanical resonators. Rather than relying on conventional (resistive) temperature sensors, we will create photodetectors that correlate absorbed radiation to the resonance frequency of an ultra-low loss micro-mechanical resonator. This method will eliminate electrical noise sources, which will allow us to reach the bolometer fundamental detection limita two orders of magnitude improvement over current performances. If successful, our work will help bring to life the potential applications of IR and THz science in sensing, security, and medical diagnosis, which are often limited by poor detector performances. ******Our third objective is to enhance the sensitivity of vibration sensors. The response of a mechanical system to external vibration is enhanced by its quality factor (up to several millions) at its natural resonance frequency. This enhancement is however never harnessed in accelerometers as it would allow sensing only at one fixed frequency out of a complex broad-band excitation spectrum. We will break this limitation using our recent demonstration of frequency-tunable high quality factor resonators. Applying resonant enhancement to a broad frequency spectrum will allow us to reach the fundamental accelerometer noise limit, a two orders of magnitude improvement over current performances. This improvement could prove useful in existing applications (e.g., early machine failure monitoring), or enable new ones (e.g. acoustic tracking of underwater vehicles).