本論文彙整對重複頻率達千赫茲的摻鐿鎢酸釓鉀再生放大器之研究， 主要工作包含改進現有系統中的脈衝延展器(pulse stretcher)、摻鐿鎢酸釓鉀再生放大器(regenerative amplifier)、脈衝壓縮器(pulse compressor)及搭建一套二倍頻式頻率解析光閘(Second Harmonic Generation Frequency-Resolved Optical Gating, SHG FROG)系統。論文內容涵蓋對於脈衝延展器與脈衝壓縮器的架設程序與檢測方法。對再生放大器性能改進的研究上，則探討脈衝於放大過程中於共振腔內的往返次數、放大器輸出脈衝重複率、輸入種子光源能量以及雷射冷卻系統溫度穩定性對輸出雷射光束的平均功率與輸出脈衝能量的影響。經放大後之雷射實驗結果可得到一脈衝重複率3 kHz，脈衝能量1.02 mJ，頻寬3.2 nm的雷射脈衝。雷射穩定度於十小時長期測試可維持於1%上下。
為獲得高尖峰功率的輸出雷射，將放大後之雷射導入脈衝壓縮器來實現飛秒級脈衝時寬，壓縮後的脈衝能量為0.77 mJ。脈衝時寬透過二倍頻式頻率解析光閘量測，為670 fs。二倍頻式頻率解析光閘從重建演算法中可得到脈衝的頻譜、頻域相位、時域以及時域相位。
在脈衝光束聚焦大小為30 μm的情況下，預期輸出之脈衝強度可達到3.25 x 1014 W/cm2。應用中可實現材料加工/表面處理或在空氣中產生雷射絲化(laser filamentation)。未經壓縮的脈衝具有1 mJ的能量，可用作下級雷射放大器的種子光源，使未來能實現一具有數十毫焦耳能量和兆瓦級尖峰功率的放大雷射脈衝。

This thesis focuses on developing a Yb:KGW regenerative amplifier operating at a kilohertz-class repetition rate. Major tasks include modifications for the pulse stretcher, the regenerative amplifier, and the pulse compressor in the existing system; in addition, a second harmonic generation frequency-resolved optical gating (SHG FROG) was constructed for characterizing the amplified pulses. Procedures for aligning the laser beam in the stretcher and verifying the quality of stretched pulses were examined first. For the improvement of the regenerative amplifier, effects of round-trip number, seed energy, and repetition rate on the average power of output beam and the energy of amplified pulse were investigated, while the temperature stability of the laser system was enhanced with a new cooling setup. Consequently, 1027-nm pulses with an energy of 1.02 mJ, a bandwidth of 3.2 nm, and a repetition rate of 3kHz were acquired from the developed regenerative amplifier. The energy stability of the output pulses can be within 1 % in a ten-hour long measurement.
To obtained a high laser peak power, the amplified pulses were subsequently introduced into a compressor to realize a femtosecond-level pulse duration. Here, the energy of compressed pulses was measured to be 0.77 mJ and the durations of them were characterized to be 670 fs by a SHG FROG, which provided temporal pulse profile, spectrum, and phases both in temporal and spectral domains of a pulse from a retrieval algorithm. With a focused size of 30 μm, it is expected that an intensity of 3.25 x 1014 W/cm2 can be realized for the output pulse to implement material machining/surface processing or drive laser filamentation in air for downstream applications. The uncompressed pulses, with an energy of 1 mJ, are also suitable for seeding a next-stage power amplifier for realizing pulses with a multi-ten-millijoule energies and a terawatt-level peak power in the future.

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