雷射技術及時析光譜研究奈米光電材料與結構之研究

Abstract

本實驗室多年來對雷射系統之動力學有深入的研究，利用高斯光束之複數q參數和 ABCD律得到q參數的疊代映像，加上Greene的留數定理來討論保守系統的穩定性。我們發 現當雷射操作在某些擁有低階共振的共振腔結構時，會產生分岔不穩的現象。這些結構對 應於所謂的橫模簡併。這些不穩定現象包括光渾沌現象都發生在虛光欄克爾雷射鎖模操作 在這些簡併腔結構附近。在極小光斑幫浦下，我們可直接產生單頻瓶形雷射光束。此外， 我們以超快時間解析泵-探技術量測到在只有60 A寬的量子井之砷化銦鎵與氮砷化銦鎵單 層量子井載子動力學行為。 在本三年計劃中，我們預計分年購買鈦藍寶石雷射倍頻套件、寬頻雷射鏡組、聲光調 變器、高頻訊號產生器及高頻鎖相放大器等設備與組件。基於以上的經驗從事下列三個研 究課題： (A)超低閥值之雷射系統建立機制及其應用；(B)由渾沌自適(self-adjusting)到自 啟動虛光闌克爾鎖模雷射動力學研究；和(C) 超快時析光譜技術研究奈米光電材料與結構 之載子動態機制。

In our previous studies, we have studied the dynamics of laser systems. We analyzed the dynamic stability of the systems by the iterative map of q parameter of Gaussian beam using the ABCD matrix with the Greene』s residue theorem. We found that the laser system possesses bifurcation when it was operated in certain so-called low order resonance cavities that correspond to the transverse mode degenerate cavities. These laser instabilities including optical chaos occurred in the soft aperture Kerr-Lens mode locking lasers operating around the degenerate configurations. Under small pump spot-size, we have directly generated single-frequency bottle laser beam from a simple laser. Furthermore, we have measured the carrier dynamics of InGaAs(N) single quantum well (only 60A width) by using ultrafast time-resolved photoreflectance. Base on the experience of the above-mentioned, in this three-year project, we plan to purchase and setup the second (third) harmonic of Ti:sapphire laser kit, broad band laser mirrors, AO modulator, high frequency function generator and lock-in amplifier, etc. to explore the following subjects: (A) the mechanisms and the applications low threshold lasers; (B) the laser dynamics of the self-adjusting chaos to self-starting soft aperture Kerr-Lens mode locking, and (C) the carrier dynamics of nano-photonic materials and structures by using ultrafast time-resolved spectroscopy.