2.7載波週期之光場量測與控制

Measurement and control of 2.7-carrier-cycle optical field

翁敬哲(Ching-Tzer Weng)

指導教授 ： 楊尚達

國立清華大學/電機資訊學院/光電工程研究所/碩士(2014年)

https://doi.org/10.6843/NTHU.2014.00086

摘要

數個週期的近紅外光超短脈衝，對應的脈衝寬小於10飛秒(fs)，由於它們超高的時間解析度、超寬的頻譜範圍與超強的強度峰值，目前已經受到相當好的關注。他們被用於各種不同的應用上，比如時間解析光譜儀和極紫外光與X射線孤立脈衝的高階倍頻產生。然而超短脈衝在介質傳遞時較易產生時間上的展寬，等於強加一個頻譜相位調變在輸入脈衝上。因此，對於在一些應用上能夠維持與控制超短脈衝波形來說，超短脈衝的振幅與相位資訊是相當重要的。目前已經有一些量測技術能解析數週期脈衝的電場資訊，它們都仰賴未知脈衝的非線性轉換訊號。在這篇論文，我們成功地提出以及證明藉由脈衝塑形器輔佐之修正場自相關干涉量測法"shaper-assisted modified interferometric field autocorrelation(MIFA)"與40微米厚的BBO能夠解析7.2飛秒、16披焦耳(pJ)近轉換極限極弱脈衝的頻譜相位，且中心波長為800奈米。實驗結果證明了這個方法的高準確性與重複性。我們的方法十分有吸引力，有幾項優點：(1)厚非線性晶體所對應的極高靈敏度。(2)不需要耗時的迭代演算。(3)量測與脈衝塑形的融合能夠得到任意脈衝波形。(4)簡易的實驗架構能避免環境干擾從而得到高穩定性。

關鍵字

超快光學 ； 脈衝量測

並列摘要

Few-to-single cycle near-infrared pulses, with temporal envelop widths less than ten femtoseconds (1fs = 10-15 s), have received great attention for their ultrahigh time resolution, ultrabroad spectral range and enormous peak intensity. They have been used in versatile applications, such as time-resolved spectroscopy and high harmonic generation of isolated EUV (extreme ultraviolet radiation) /X-ray pulses. However, ultrashort optical pulses are prone to temporally broadened due to the dispersion of optical mediums, which introduce a spectral phase modulation upon the input pulse. Therefore, detailed information (amplitude and phase profiles) of ultrashort optical pulses is highly significant in terms of maintenance and control of the ultrafast waveforms in some applications. There have been a couple of measurement techniques that can retrieve the electric field of few-cycle pulses. Most of them rely on the nonlinearly converted signal of the unknown optical pulse. In this thesis, we proposed and experimentally demonstrated the shaper-assisted modified interferometric field autocorrelation (MIFA) method for retrieving the spectral phases of weak (16 pJ) 7.2 fs nearly transform-limited pulse and tailored waveforms at 800 nm by using a 40-um-thick BBO. Experiment results confirm the high accuracy and reproducibility of this method. Our method is attractive in terms of: (1) inherently high sensitivity arisen from using thick nonlinear crystal, (2) free of time-consuming iterative data inversion, (3) access to the desired waveform at the point of experiment by integration of measurement and shaping, (4) high stability against environmental perturbation due to the nearly common-path configuration.

並列關鍵字

Ultrafast optics ； Pulse measurement

參考文獻

1. A. Yabushita, Y. H. Lee, and T. Kobayashi, “Development of a multiplex fast-scan system for ultrafast time-resolved spectroscopy,” Review of Scientific Instruments 81 (2010).

3. A. Baltuska, M. S. Pshenichnikov, and D. A. Wiersma, “Amplitude and phase characterization of 4.5-fs pulses by frequency-resolved optical gating,” Optics Letters 23, 1474-1476 (1998).

4. S. Akturk, C. D’Amico, and A. Mysyrowicz, “Measuring ultrashort pulses in the single-cycle regime using frequency-resolved optical gating,” Journal of the Optical Society of America-B-Optical Physics 25, A63-A69 (2008).

5. L. Gallmann, D. H. Sutter, N. Matuschek, G. Steinmeyer, U. Keller, C. Iaconis, and I. A. Walmsley, “Characterization of sub-6-fs optical pulses with spectral phase interferometry for direct electric-field reconstruction,” Optics Letters 24, 1314-1316 (1999).

6. A. M. Weiner, “Femtosecond pulse shaping using spatial light modulators,” Review of Scientific Instruments 71, 1929-1960 (2000).