2017-01-012024-05-18https://scholars.lib.ntu.edu.tw/handle/123456789/699088摘要：在前一期計劃中，本實驗室領先全球發現單一金屬奈米粒子的光學散射具有非線性，並可提高光學顯微技術解析度。在超解析顯微領域，提供一種全新光學對比，發表在Physical Review Letters上。此計劃將拓展前述主題，先從非金屬的非線性研究開始，鎖定比金耐熱且與半導體製程相容的電漿子材料TiN，並往基礎與應用端延伸。 在基礎物理部分，方向有二。一是對於我們發展的電漿子飽和激發技術，在金屬/非金屬上建立非線性與解析度的定量關係，同時找尋解析度極限；初步實驗已觀察到單點影像可下降到20奈米之寬度，是目前仰賴飽和提高解析度技術的世界紀錄。二則是釐清此非線性現象的物理機制，初步猜想是源自光學激發熱效應。我們會和以色列團隊合作，對金屬/非金屬奈米粒子受光激發的溫度效應進行理論與實驗上的驗證，並以此理論發展光熱影像超解析技術。 在應用方面則有三個主要方向。一是配合近紅外光及適當的奈米結構，實現在超過1mm深層組織中得到次繞射極限解析度，這將是世界上第一個能在這種深度得到超解析的技術。二是實現由單一金屬/非金屬奈米粒子構成，可在室溫操作的積體光路全光學開關。三則是建立一套系統，可以快速量測單一奈米結構的非線性吸收/散射係數，對未來相關研究會很有幫助。 <br> Abstract: Under the support of MOST, we have found novel nonlinear optical scattering from a single metallic nanoparticle, and have applied the nonlinearity to significantly enhance spatial resolution, providing an innovative non-bleaching contrast in the field of superresolution microscopy. Our results was not only published in the prestigious Physical Review Letters, but also highlighted by editors of PRL and Nature Photonics. In this project, we will extend our previous finding in both fundamental and applied physics, with several major topics. 1. (applied) To achieve deep-tissue superresolution observation. Among current superresolution techniques, SAX exhibits the best potential for deep-tissue imaging due to its point-scan nature and no need of phase engineering. In addition, the resolution of plasmonic SAX is much better compared to fluorescence SAX. We will setup a near-infrared-compatible scanning SAX system, incorporate plasmonic particles that are resonant at 700–1000 nm, and realize sub-diffraction-limit resolution in 1-mm depth of biological tissue. It will be a key breakthrough in optical imaging field. 2. (fundamental) To establish a quantitative relationship between plasmonic nonlinearity and spatial resolution, based on saturated excitation microscopy (SAX), in search for the limit of resolution. From our preliminary result, at very high demodulation frequency, the point spread function width can reach 20 nm, setting the world record of saturation-based superresolution imaging. 3. (applied) To realize ultrasmall room-temperature all-optical switch based on single metal/non-metal nanostructure. Our preliminary result has demonstrated efficient all-optical modulation in a single gold nanoparticle, with <0.001 m3 mode volume, >80% modulation depth, and ~100-nm broadband operation. However, gold has poor thermal resistance, and is not compatible with current semiconductor fabrication. We will adopt a novel material, TiN, which is fab-compatible, to establish plasmonic all-optical switch in the format of integrated optical circuits, paving the way toward future all-optical computing. 4. (applied) To setup a laser scanning system that is capable of quick quantification of nonlinear absorption/scattering efficiency and the corresponding real/imaginary nonlinear index in a single nanostructure. Compared to conventional “z-scan” technique that measures the ensemble nonlinear response among nanoparticles, this new system will provide information individually, and will be very valuable for future detailed nano-nonlinear researches. 5. (fundamental) To collaborate with Israel researchers to quantitatively clarify the underlying mechanism of the plasmonic nonlinearity, which may be due to photothermal effects. We will study theoretically and experimentally the intensity and temperature dependence of metal/non-metal plasmonic resonance. The knowledge will lead to development of super-resolved photo-thermal imaging techniques, which will be able to observe very small nanoparticles in biological samples.電漿子共軛焦顯微鏡plasmonicsconfocal microscope,