瞬態光譜學是一種用於材料檢測的強大工具，其有助於進一步分析和理解材料內部激子、載子的行為以及能量轉換的過程，而瞬態光致發光光譜學著重於利用螢光光譜解析激發態電子回到基態的動態。目前，具有優於皮秒級時間解析能力的瞬態光致發光技術包括螢光上轉換光譜學、光學克爾門閘光譜學和瞬態光柵光致發光光譜學(TGPLS)。其中，TGPLS 技術因其能夠測量寬頻光譜並同時具有低背景訊號而成為本研究的重點。

上述具有優於皮秒級時間解析能力的瞬態光譜技術皆採用泵浦-探測方法來捕捉材料在不同激發延遲時間下的光譜變化。泵浦脈衝和探測脈衝的脈衝持續時間共同決定了測量系統的時間解析能力。因此，利用超短脈衝作為光譜量測的光源，可以有效提升系統的時間解析能力。目前，通過超連續光譜產生來獲取超寬頻的脈衝是實現超短脈衝常用的其中一種方法。在補償超連續光譜產生過程中非線性效應和材料引起的色散後，脈衝寬度可達到飛秒甚至埃秒等級。

本研究中開發的瞬態光柵光致發光技術系統使用摻鐿雷射，其中心波長為1030 nm，脈衝持續時間為190 fs，重複頻率為25 kHz。通過多重薄片連續光譜技術將脈衝持續時間壓縮到49 fs，實現了78 fs 的儀器響應函數（IRF），超越了先前的時間解析度工作(200 fs)。在實際量測由國立台灣大學化學系周必泰老師實驗室所提供的DPNA-tBu 後，更是成功解析到小於80 飛秒的分子內動態行為，證明了此技術在研究材料的超快激發態動態方面的優越性能。

Transient spectroscopy is a powerful tool used for material characterization. It aids in the further analysis and understanding of the behavior of excitons and carriers, as well as the energy transfer processes within materials. Transient photoluminescence (PL) spectroscopy, in particular, focuses on utilizing fluorescence spectra to resolve the dynamics of excited-state electrons returning to the ground state. Transient PL techniques with time resolution at the picosecond level or better include fluorescence up-conversion spectroscopy, optical Kerr gate spectroscopy (OKGS), and transient grating photoluminescence spectroscopy (TGPLS). Among these, the TGPLS technique stands out for its ability to measure broadband spectra with low backgrounds, making it the primary focus of this thesis.

The aforementioned transient PL techniques employ the pump-probe method to capture the spectral changes in materials at different excitation delay times. The pulse duration of both the pump and probe pulses determines the temporal resolution of the measurement system. Therefore, using ultrashort pulses as the light source for spectroscopic measurements can enhance the system’s temporal resolution. One of the popular methods to achieve ultrashort pulses is using supercontinuum generation (SG) to obtain ultra-broad bandwidths. After compensating for nonlinear effects and material-induced dispersion during the SG, the pulse duration can be achieved on a few femtoseconds or attoseconds.

The TGPLS system developed in this work utilizes a Yb-based laser with a central wavelength of 1030 nm, a pulse duration of 190 fs, and a repetition rate of 25 kHz. The pulse duration is compressed to 49 fs using the multiple plate continuum (MPC) module, resulting in an instrument response function (IRF) of 78 fs. This setup surpasses previous works in temporal resolution (200 fs). After conducting
actual measurements on DPNA-tBu provided by Professor Bi-Tai Chou’s laboratory in the Department of Chemistry at National Taiwan University (NTU), we successfully resolved intramolecular dynamics within less than 80 femtoseconds. This demonstrates the superior performance of this technique in studying ultrafast excited-state dynamics in materials.

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