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題 名 | 使用超短脈衝雷射研究奈米聲波=Nano Acoustic Waves Studies Using Ultrashort Pulse Lasers |
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作 者 | 林宮玄; 陳嘉維; 孫啟光; | 書刊名 | 國立臺灣大學工程學刊 |
卷 期 | 88 2003.06[民92.06] |
頁 次 | 頁3-12 |
專 輯 | 「電機工程」專輯 |
分類號 | 334.2 |
關鍵詞 | 奈米; 奈米聲波; 壓電; 奈米超音波; Nanometer; Nano acoustic waves; Piezoelectric; Nano ultrasonics; |
語 文 | 中文(Chinese) |
中文摘要 | 本文報導如何使用超短脈衝雷射在氮化銦鎵╱氮化鎵多重量子井上產生波長約十奈米的聲波。運用約200飛秒(~ 2 × 10–13秒)的紫外光短脈衝雷射可改變氮化鎵材料量子井中的壓電電場,因此產生了應變的變化,進而產生聲波並開始傳播。本文簡介聲波產生的理論,並分析不同量子井結構與產生之奈米聲波的波形關係。另外,不同於以往所產生的聲波脈衝(shock wave),我們產生了具有相位資訊的奈米聲波,並以實驗示範如何用兩個基頻相同相位差80°的奈米聲波產生二倍頻率的聲波。有了聲波波形、相位的控制技術,奈米聲波源將可應用到奈米解析度的超音波技術或兆赫頻率之聲電效應等研究。 |
英文摘要 | In this paper, we report the acoustic wave generation with ~ 10 nm wavelength on InGaN/GaN multiple quantum wells by using ultrashort pulse lasers. In piezoelectric GaN materials, we use ~ 200 fs UV short optical pulses to induce the piezoelectric field sudden modefication in the quantum wells. Due to the sudden change of the piezoelectric field, the strain also changes and the induced acoustic waves start to propagate. We report the theory of nano acoustic wave generation and analyze the relation between different structures of multiple quantum wells and waveforms of induced nano acoustic waves. Besides, we generate nano acoustic waves with accurate and coherent phase informations, which are different from previously reported picosecond shock waves. We also demonstrate how to generate the second harmonic nano acoustic waves by using two nano acoustic waves with the same fundamental frequency but with 180-degree-different phases. With the technology to control the waveform and the phase, nano acoustic wave can be applied to many studies such as ultrasonic imaging with nanometer resolution and tera-herz devices based on nano-acouto- electric effects. |
本系統中英文摘要資訊取自各篇刊載內容。