雷射驅動電漿天線是種擁有高峰值功率、頻率可調且低成本的輻射源。相對於其他高功率的輻射源，例如自由電子雷射、同步輻射以及返波振盪器等，雷射驅動電漿天線的使用架設上較為方便，且體積較小、成本也較為低廉。因此在本論文中，我們將專注於雷射驅動電漿天線的實作量測與機制分析。為了在材料中產生足夠強的電漿波振盪，我們架設了一套二級Nd:YAG雷射放大器系統，產生了脈衝能量70毫焦耳、脈寬550皮秒的1064奈米雷射脈衝。由於此雷射脈衝的光程約在S-band輻射的波長尺度範圍之內，因而有能力激發產生S-band頻率的電漿波振盪。以此作為基礎，我們設計了以雷射驅動的單極導線天線，其產生的輻射波長為天線總長的四倍，是為四分之一波長天線。實作上為將此高能量的雷射脈衝聚焦於不同長度的銅導線之上，我們便能以環形天線測量到頻率範圍1至2.5 GHz的輻射。此外，我們也展示了將此雷射驅動天線結合S-band矩形波導並誘發產生橫向電場模態，並且從 模態中量測到了頻率高於5 GHz的輻射。在最後我們探討了增強輻射強度的方法與其潛力。我們將原Nd:YAG雷射放大器系統的第二級擴充為四通放大器，並將輸出的雷射脈衝能量提升至約120毫焦耳。我們更進一步地分析實驗系統的量子效率，在氣壓約為10-9 torr的高真空中，以波長為266奈米的雷射脈衝激發金屬天線，測得量子效率約為 。最終，將實驗的量測結果結合以上的優化條件，我們評估此雷射驅動電漿天線的峰值功率可達到37千瓦。

Laser-driven plasmonic antenna is a cost-efficient, high peak power, and tunable radiation source. Contrasted with other high-power radiation sources, such as free electron laser, synchrotron, and backward-wave oscillator, laser-driven plasmonic antenna is much more convenient, small-scale and lower cost. In this work, we focus on demonstrating and analyzing the mechanisms of laser-driven plasmonic antenna. In order to induce strong plasmonic oscillation inside the materials, a two-stage Nd:YAG laser amplifier system has been established, generating laser pulse at 1064 nm with ~70 mJ pulse energy and ~550 ps pulse width. The optical length of this laser pulse in space is comparable to the wavelength of S-band radiation, and it is able to induce plasmonic oscillation in the S-band frequencies. As a result, we designed a laser-driven monopole antenna, generating radiation in the wavelength of four times the antenna’s full length. With intense laser pulse focusing onto the copper wires of different lengths, we have measured radiation from 1 to 2.5 GHz by a small loop antenna. Furthermore, we have demonstrated the capability of a wire antenna to induce transverse electric modes inside an S-band rectangular waveguide. Radiation frequency higher than 5 GHz has also been generated from the waveguide mode. Lastly, the potentials of enhancing radiation power are discussed. The maximum pulse energy of the two-stage Nd:YAG laser amplifier system has achieved ~120 mJ by extending the second-stage to a four-pass amplifier system. We also demonstrated a quantum efficiency of by a 266 nm laser pulse under a vacuum pressure of ~10-9 torr. Under these optimized conditions, the peak power of a laser-driven plasmonic antenna is estimated to be 37 kW.

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