本論文利用雙光子螢光光譜和z-scan量測系統進行了鈣鈦礦，包括MAPbBr3單晶和CsPbBr3量子點薄膜的雙光子吸收效應之研究。利用飛秒鈦藍寶石雷射作為鈣鈦礦樣品的泵浦光源，可以分別獲得由自由激子復合與自由載子複合的CsPbBr3量子點薄膜和MAPbBr3雙光子激發之螢光光譜，透過擬合雙光子螢光光譜強度與激發雷射強度的冪次定律關係，可獲得線性方程的斜率接近二，證明了所製備的鈣鈦礦具有雙光子吸收特性。此外我透過溫度相依雙光子螢光光譜特性之量測，藉由擬合螢光強度對溫度之關係可以得到MAPbBr3單晶和CsPbBr3量子點薄膜的激子束縛能分別為50.3 meV與52 meV，並且由螢光光譜之變寬歸咎於激子與縱向聲子之交互作用。本實驗中我也利用800奈米脈衝雷射光源進行Z-scan量測可以獲得雙光子吸收係數，證明CsPbBr3量子點薄膜具備較大的雙光子吸收係數約150 cm / GW，推論是由於受到量子侷限效應。最後，將MAPbBr3單晶和CsPbBr3量子點薄膜作為干涉式自相關儀的非線性介質進行被動鎖模鈦藍寶石雷射的脈衝量測。將量測到自相干波形經過理論擬合後，成功獲得約110 fs的脈衝。這項工作證明了有機-無機和無機三鹵化物鈣鈦礦可以作為超快短脈衝中便捷且低成本的非線性吸收材料。

Two photon absorption (TPA) of perovskite including MAPbBr3 single crystal (SC) and CsPbBr3 quantum dot (QD) films have been investigated by the TPA photoluminescence (PL) and z-scan measurement in this thesis. By the intensity dependent PL using the fs Ti:sapphire laser as a light source, TPA effect has been demonstrated through the power law fitting to reveal the exponent around 2. Besides, temperature dependent TPA PL has been applied for MAPbBr3 SC and CsPbBr3 QD films to obtain the binding energy around 50.3 meV and 52 meV, respectively, and shows the interaction between exciton and LO phonon. Owing to the quantum confinement effect, the relatively large TPA coefficient of CsPbBr3 QD films around 150 cm/GW has been demonstrated by the Z-scan measurement. Finally, I used the TPA PL from both MAPbBr3 SC and CsPbBr3 QD films in combination of the interferometric autocorrelator to obtain the pulse duration of passive mode-locked Ti:sapphire laser around 110 fs. This work demonstrates the possibility of inorganic-organic and inorganic trihalide perovskites as a convenient and low-cost nonlinear absorber for applications in ultrafast photonics.

摘要 i
ABSTRACT ii
致謝 iv
Content v
List of Figure vii
List of Table x
Chapter 1. Introduction 1
1.1 Historical perspective of halide perovskite 1
1.2 Nonlinear absorption of halide perovskite 4
1.3 Applications of nonlinear optics from perovskite 6
1.4 Motivation 9
Chapter 2. Theoretical background 10
2.1 Z-scan 10
2.1.1 Laser light propagates in space 11
2.1.2 Linear and nonlinear transmission 11
2.1.3 The relationship between transmittance and TPA coefficient 12
2.2 Autocorrelator 13
2.2.1 interferometric autocorrelator 13
Chapter 3. Experimental setup 16
3.1 Photoluminescence (PL) measurement 16
3.1.1 PL measurement 16
3.1.2 Temperature dependent PL and photon lifetime measurement 17
3.2 Setup of z-scan 19
3.3 Interferometric autocorrelator 20
Chapter 4. Result and Discussion 23
4.1 Optical properties of halide perovskite 23
4.1.1 Absorption and PL spectrum of MAPbBr3 single crystal (SC) 23
4.1.2 Absorption and PL spectrum of CsPbBr3 Quantum Dots (QDs) 27
4.1.3 Intensity dependent TPA PL spectrum 30
4.2 Temperature dependent PL spectrum 32
4.2.2 Linewidth of PL spectrum 34
4.2.3 Temperature related photon decay trace of CsPbBr3 37
4.3 Two-photon absorption coefficient 39
4.4 Autocorrelation trace of fs mode-locked pulse 43
Chapter 5. Conclusion 44
Reference 45

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