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Title: | 奈米晶矽方塊之光熱效應致雙穩態散射 Photothermal Bistability Scattering in a Single Crystalline Silicon Nanoblock |
Authors: | 陳育傑 Yu-Chien Chen |
Advisor: | 朱士維 Shi-Wei Chu |
Keyword: | 光學雙穩態,矽光子學,光熱效應雙穩態,有限元素法,解析度提升, optical bistability,photothermal bistability,finite element method,silicon photonics,resolution enhancement, |
Publication Year : | 2023 |
Degree: | 碩士 |
Abstract: | 雙穩態系統在生活中十分的常見,特別是在數位電路中的正反電路。正反電路是電子產品中最主要的元件之一,藉由產生0 與1兩個穩定態來儲存二進位數位資料。近幾十年來,光學雙穩態越來越受到關注,因為它提供了高速光學正反電路可以解決電子電路調制時間較慢的問題,此外也有許多其他應用,例如光儲存器等等。光學雙穩態的組成條件為共振腔以及非線性介質,在所有的非線性材料中,矽基光學雙穩態備受關注,基於矽在現今的製程上有具有較高相容性和高折射率的特性,能夠有更強的光限制性,然而矽材料自身的非線性較小(10^-9微米平方每毫瓦),因此藉由提升共振腔的品質因子來增強光學雙穩態的非線性響應,為了提升品質因子,矽共振腔的大小通常在微米的大小,這對於光積體電路來說是個缺點。最近我們結合光熱效應與米氏共振設計出低品質因子奈米方塊共振腔,並將非線性折射率提高到10^-1微米平方每毫瓦,這有效的提高了光學的非線性,因此我們利用同樣的概念,利用低品質因子奈米方塊共振腔達到光熱效應雙穩態。
在本研究中,藉由驗證過的模擬模型在特定的雷射光波長之下模擬激發強度依賴性並預測哪種尺寸的奈米方塊具有光熱效應雙穩態,此外我們針對具有光熱效應雙穩態的奈米結構,利用數值模擬,證明光熱效應雙穩態同時會伴隨著遲滯效應。為了能夠證明光熱效應雙穩態普遍存在於矽奈米結構中,我們藉由數值模擬,藉由調整雷射光波長,使得原本沒有光學雙穩態現象的奈米結構,也有光學雙穩態,證明了光熱效應雙穩態的普遍性。除此之外,我們模擬雷射掃描影像,並提出超解析的應用。最後我們用測量結果證明了光熱雙穩態的預測。我們的研究設計出目前尺寸以及品質因子皆最小的雙穩態共振結構。 Bistability is commonly used in electronics flip-flop circuits. It generates two stable states to store binary digital information. In recent decades, optical bistability becomes popular, because it offers optical flip flops leading to applications such as optical memory. Optical bistability is composed of a resonator and a nonlinear medium. Silicon-based optical bistability has drawn much attention among all kinds of nonlinear mediums. Since silicon has stronger light confinement. However, the intrinsic Kerr nonlinearity of silicon n_2 is 10^-9 μm^2/mW. We need high Q resonators to enhance the nonlinear response of optical bistability. We recently discovered that the Mie-enhanced photothermal effect in a low Q factor resonator increases the nonlinear refractive index up to 10^-1 μm^2/mW. Therefore, we can achieve photothermal bistability in a low Q-factor silicon resonator. In this work, we use a validated numerical simulation model to simulate the excitation intensity dependence under certain laser wavelengths and predict which size of the particle has photothermal bistability. In addition, we have conducted a validated simulation model to demonstrate that photothermal bistability is accompanied by hysteresis effects. To show the generality of photothermal bistability, we conducted numerical simulations. By adjusting the wavelength of the laser light, we can induce optical bistability in nanostructures that originally did not exhibit such behavior. This provided evidence that photothermal bistability can be observed in nanostructures of different sizes under different laser light wavelengths. Moreover, we simulate the laser scanning images and provide a possible application of super-resolution enhancement. Last but not least, we offer a preliminary experimental result to demonstrate the existence of photothermal bistability in silicon nanostructures. Our study designs a bistable nanostructure with the smallest size and Q factor so far. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/90481 |
DOI: | 10.6342/NTU202301642 |
Fulltext Rights: | 同意授權(全球公開) |
Appears in Collections: | 物理學系 |
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File | Size | Format | |
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ntu-111-2.pdf Until 2025-07-19 | 2.85 MB | Adobe PDF |
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