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

我的项目的总体理念是利用基础纳米尺度科学的最新进展，并将其转化为新的颠覆性应用技术。遵循这一理念，我们的具体目标是利用(1)纳米级热输运和(2)光力学领域的最新进展，创造一种新型的光热机械微系统。这些微系统的潜在应用分为三个子目标：(1)直接热电转换，(2)高精度红外和太赫兹光探测，(3)高精度振动传感。我们的第一个目标是利用近场热光伏（NFTPV）效应，为热能发电创造新的便携式解决方案。原理是构建模块，其中来自热源的能量辐射到一个特别定制的光伏电池，放置在其极端接近，通常小于100纳米，以提高性能。我们将开发高温微机械系统，允许这种低于100纳米的距离控制，并将其与光伏电池集成。我们的目标是实现这项技术的首次演示，从长远来看，它比现有的热电发电机有更高的转换效率。我们的第二个目标是利用光机械谐振器提高红外（IR）和太赫兹（THz）光电探测器的检测极限。而不是依靠传统的（电阻）温度传感器，我们将创建光电探测器，将吸收的辐射与超低损耗微机械谐振器的共振频率相关联。这种方法将消除电噪声源，这将使我们达到测辐射热计的基本检测极限，比电流性能提高两个数量级。如果成功，我们的工作将有助于实现红外和太赫兹科学在传感、安全和医疗诊断方面的潜在应用，这些应用通常受到探测器性能差的限制。我们的第三个目标是提高振动传感器的灵敏度。机械系统对外部振动的响应在其固有共振频率下由其质量因子（高达数百万）增强。然而，这种增强从未在加速度计中得到利用，因为它只允许在复杂的宽带激励频谱中的一个固定频率上进行传感。我们将利用我们最近的频率可调高质量因数谐振器的演示来打破这一限制。将共振增强应用于宽频谱将使我们能够达到加速度计的基本噪声极限，比当前性能提高两个数量级。这一改进可能在现有应用（如早期机器故障监测）或新应用（如水下航行器的声学跟踪）中被证明是有用的。

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).