本論文透過double pulses對pump-probe系統的材料載子做激發，探討第一個載子激發後到第二個載子激發過程中間的載子動力學問題，觀察double pulses之間delay大小對載子激發後life time的影響，作為往後兆赫輻射波實驗的基礎資料。
此外，我們利用麥克森干涉儀產生具有時間延遲且振幅與波長都相同的兩道光脈衝，且藉由在時間延遲為0.5ps的兩道光雙脈衝激發兆赫波輻射，排除雙脈衝激發兆赫波時的拍頻濾波效果，並且利用雙脈衝的量子同調的建設性干涉，獲得高頻power大，且頻寬寬的兆赫波輻射訊號。

In this thesis, carrier dynamics and broadband THz enhancement of photoconduction based THz system are studied with double pulses pump-probe and THz system.
The carrier dynamics behavior of the second pulse excitation almost remain unchanged for various temporal spacing of double pulses excitation (from 264fs to 276fs). This is attributed to faster carrier life time of material (around 270fs).
Meanwhile, broadband THz enhancement is also investigated under various chirp and temporal spacing of two excitation pulses using shaping pulse THz-TDS system. Compared to typical narrowband THz enhancement, enhanced broadband THz signal both in temporal profile and power is observed at specific temporal spacing and chirp of two excitation pulses. Suitable mechanics is also discussed in this thesis.

摘要......................................................Ⅰ
ABSTRACT...............................................Ⅱ
誌謝......................................................Ⅲ
目錄......................................................Ⅳ
圖表目錄..................................................Ⅵ
第一章 緒論................................................1
1-1節 前言...............................................2
1-2節 兆赫輻射產生原理...................................5
1-2-1 光電導機制..................................................5
1-3節 兆赫輻射偵測原理...................................8
1-3-1 偵測使用光導天線(PC sampling)............................... 8
1-3-2 自由空間電光取樣法(EO sampling)............................ 11
1-4節 動機............................................. 13
第二章 脈衝整型機制.......................................15
2-1節 脈衝形變原理..................................... 16
2-1-1 光脈衝整形原理............................................ 16
2-1-2 光脈衝整形系統(pulse shaper)................................ 18
2-2節 色散補償與最短脈衝............................... 20
2-2-1 相位凍結演算法(Freezing algorithm) .......................... 20
2-2-2 相位凍結演算法配合脈衝整形系統獲得最短脈衝............... 23
2-3節 結論............................................. 25
第三章 雙脈衝的載子激發之載子動力學機制...................26
3-1節 泵探量測技術原理..................................27
3-2節 雙脈衝激發的泵探量測實驗與探討................... 30
3-2-1 實驗架構..................................................30
3-2-2 實驗數據討論..............................................31
3-2-3 利用載子激發動力學探討載子生命週期........................35
3-3節 結論............................................. 38
第四章 寬頻兆赫輻射增強實驗與數據討論.....................39
4-1節 實驗架構與事前工作............................... 40
4-1-1 兆赫輻射時析光譜系統架構(THz-TDS system) ................ 40
4-1-2 二階色散(啾頻)所對應脈衝寬度的V-curve.................... 42
4-2節 調變啾頻之兆赫輻射增強........................... 44
4-2-1 啾頻大小對兆赫輻射時域上強度的影響....................... 44
4-2-2 啾頻大小對兆赫輻射頻域上頻譜的影響....................... 46
4-2-3 結論..................................................... 48
4-3節 調變啾頻與雙脈衝間距之兆赫輻射增強............... 49
4-3-1 啾頻大小對雙脈衝兆赫輻射時域與頻域上的影響............... 49
4-3-2 延遲大小對雙脈衝兆赫輻射時域與頻域上的影響............... 52
4-3-3 寬頻兆赫輻射的增強....................................... 54
4-3-4 結論..................................................... 57
第五章 總結與未來展望.....................................58
5-1節 總結...................................................... 59
5-2節 未來工作.................................................. 61
第六章 參考文獻...........................................62

1.B.Ferguson,X.C.Zhang,“Materials for terahertz science and technology,” nature material , 1 , 26-33(2002)

2.T. G. Phillips and J. Keene,“Submillimeter astronomy,” Proc.IEEE 80, 1662 (1992)

3.李青翰,林凡異,“兆赫波漫談”,物理雙月刊三十一卷, 97~108, (2009)

4.鐘佩鋼,顏順通,“兆赫波源之發展與原理簡介”,物理雙月刊(卅一卷二期) 2009年四月

5.M.Tonouchi, “Cutting-edge terahertz technology,” Nat. photonics1, 97 (2007)

6.W.L. Chan, J. Deibel, D.M. Mittleman, “Image with terahertz radiation,” Rep.Prog.Phy ,70 , 1352-1379 (2007)

7.黃俊凱,“氧離子佈植砷化鎵之載子動力學研究”國立中山大學光電工程研究所碩士論文 2008年4月

8.蘇偉企,“高效率波長可調兆赫輻射之研製”國立中山大學光電工程研究所碩士論文 2009年7月

9.林松輝,“利用飛秒脈衝形變技術研究光導天線輻射兆赫波之特性”
國立交通大學光電工程研究所碩士論文 2008年7月

10.C. Ludwig and J. Kuhl,“Studies of the temporal and spectral shape of terahertz pulses generated from photoconducting switches,”Appl. Phys. Lett, 69, 1194-1196 (1996)

11.S. Kono, M. Tani, and K. Sakai, “Ultrabroadband photoconductive detection: Comparison with free-space electro-optic sampling,” Appl.Phys. Lett, 79, 898-900 (2001)

12.吳宗翰,“光脈衝整形器應用於兆赫輻射波形整合之研究”國立交
通大學光電工程研究所碩士論文 2005年7月

13.Sang-Gyu Park,M. R. Melloch, and A. M. Weiner “Comparison of
terahertz waveforms measured by electro-optic and photoconductive
sampling,” Appl.Phys. Lett, Vol.73, No.22 (1998)

14.Paul C. M. Planken, H.K Nienhuys and Huib J. Bakker, Tom Wenckebach,“Measurement and calculation of the orientation dependence of terahertz pulse detection in ZnTe,”J.Opt.Soc.Am.B,18,3,313~317(2001)

15.劉信成,“脈衝整形系統在超寬頻脈衝量測與多脈衝產生之應用”國
立中山大學光電工程研究所碩士論文 2008年9月

16.Yasufumi Fujiwara,Kazuhiko Nakamura,Shoichi Takemoto,Yoshikazu
Terai,Masato Suzuki, Atsushi Koizumi, Yoshikazu Takeda and Masayoshi
Tonouchi,“ Nonequilibrium Carrier Dynamics Studied in Er,O-Codoped
GaAs by Pump-Probe Reflection Technique,” Mater. Res. Soc. Symp.Proc.
Vol. 866 (2005)

17.Donald A.Neamen,“Fundamentals of Semiconductor Physics and
Devices, ”page81(2003)

18.S. Gupta, M. Y. Frankel, J. A. Valdmanis, J. F. Whitaker,and G. A. Mourou, “Subpicosecond carrier llifetime in GaAs grown by molecular beam epitaxy at low temperatures, ” Appl. Phys. Lett., Vol. 59, No. 25, 16 December 1991

19.Farhan Rana, “Electron-hole generation and recombination rates for Coulomb scattering in grapheme, ” PHYSICAL REVIEW B 76, 155431(2007)

20.Yongqian Liu, Sang-Gyu Park, and A. M. Weiner, “Enhancement of narrow-band terahertz radiation from photoconducting antennas by optical pulse shaping, ” OPTICS LETTERS Vol. 21, No. 21 November 1, 1996

21.M. Nakajima, K. Uchida, M. Tani, and M. Hangyo, “Strong enhancement of terahertz radiation from semiconductor surfaces using MgO hemispherical lens coupler,” Appl. Phys. Lett. 85,2,191-194(2004)

22.Y. Liu, S. G. Park, and A. M. Weiner, “Enhancement of narror-band terahertz radiation from photoconducting antennas by optical pulse shaping,” Opt. Lett. 21,21, 1762-1764 (1996)

23.M. Tani, K. Sakai, and H. Mimura, “Emission characteristics of photoconductive antennas based on low-temperature-grown GaAs and semi-insulating GaAs,” Appl.Opt, 36,7853-7859 (1997)

24.S. Kono, M. Tani, and K. Sakai, “Ultrabroadband photoconductive detection: Comparison with free-space electro-optic sampling,” Appl.Phys. Lett, 79, 898-900 (2001)

25.Z. G. Lu, P. Campbell, and X.C. Zhang, “Free-space electro-optic sampling with a high-repetition-rate regenerative,” Appl. Phys. Lett. 71, 593-595(1997)

26. A. S. Weling, B. B. Hu,N. M. Froberg, and D. H. Auston,“Generation
of tunable narrow-band THz radiation from large aperture
photoconducting antennas,” Appl. Phys. Lett. 64,(2),137-139(1994)

27.A.S. Weling and D. H. Auston,“Novel sources and detectors for coherent tunable narrow-band terahertz radiation in free space,” J. Opt. Soc. Am. B,13,12,2783-2791(1996)

28.Y. C. Shen, P. C. Upadhya, H. E. Beere, E. H. Linfield, A. G.Davies, I. S. Gregory, C. Backer, W. R. Tribe, and M. J. Evans,“Generation and detection of ultrabroadband terahertz radiation using photoconductive emitters and receivers,” Appl. Phys. Lett 85,164 (2004)

29. S.-F. Horng, S.-H. Lu, J.-S. Yu, T.-R. Tsai, and C.-C. Chi,“Comparison of optical pump-probe characterization of low-temperature-grown GaAs at well-above-bandgap and near-bandedge wavelengths,” Opt. Quamtum Electron. 32, 573 (2000)

30.H. S. Loka, S. D. Benjamin, and P. W. E. Smith, “Optical characterization of low-temperature-grown GaAs for ultrafast all-optical switching devices,” IEEE. J. Quantum Electron. 34, 1426(1998)