我的工作主要是利用非線性效應拓展脈衝光的頻寬並壓縮其持續時間，從而產生具有高峰值功率的前級脈衝光源，此光源未來將應用於產生極紫外光（EUV）及相關的研究。實驗室未來計劃使用頻率梳雷射（frequency comb laser）作為驅動光源。該雷射具有高重複率（~MHz）和微焦耳至奈焦耳級（μJ、nJ）的功率輸出光源。這種光源中不同頻率成分的相位在時間上是明確且穩定的，其可應用於精確頻率測量、光學鐘以及超快科學等研究領域。然而，目前實驗室沒有頻率梳光纖雷射，我使用實驗室已有的商用脈衝雷射(PHAROS Femtosecond Lasers) 作為驅動光源，以驗證此方案。
由於高能脈衝雷射的頻寬受到增益介質增益帶寬的限制，使得其頻寬相對較窄。脈衝需要透過拓展頻寬並壓縮脈衝持續時間的方式來獲得高峰值功率。本論文探討了使用商用摻鐿鎢酸釓鉀晶體脈衝再生放大器雷射，輸出微焦耳等級脈衝能量，並通過固態多通腔體與氣體多通腔體的非線性效應實現頻譜拓展與脈衝壓縮。我將驅動光源經第一級展頻壓縮架構，使脈衝持續時間從172飛秒壓縮至46飛秒。在第二級展頻中，端對端頻寬從64.25奈米拓展至600奈米，並推算其變換極限脈衝可實現5.6飛秒的理想脈衝持續時間。該成果是實現微焦耳級單周期脈衝光源的重要一步。

Our lab is dedicated to developing high-peak-power seed pulse sources for generating bright EUV light, with further applications in related research. In the future, we aim to use frequency comb lasers as the driving source. These lasers feature high repetition rates (~MHz) and μJ- to nJ-level pulse energies with temporally stable phase relationships among different frequency compo-nents, making them suitable for precision frequency measurements, optical clocks, and ultrafast science. However, due to the unavailability of frequency comb fiber lasers, we used a commercial fs laser as the driving source for our experiments.
The bandwidth of high-energy pulsed lasers is limited by the gain medium, resulting in relatively narrow spectral widths. To achieve higher peak powers, spectrum broadening and pulse compression are essential. This study demon-strates the use of a commercial Yb:KGW regenerative amplifier laser to achieve spectral broadening and pulse compression, realizing efficient micro-joule-level pulse output. Through the first-stage broadening and compression setup, the pulse duration was compressed from 172 fs to 46 fs. In the second stage, the spectral bandwidth was extended from 64.25 nm to 600 nm, with the transform-limited pulse duration estimated to be 5.6 fs. This achievement marks an important step toward realizing microjoule-level single-cycle pulse sources.

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