在本論文中，我們提出並以實驗證實了如何在超密非週期准相位匹配光學超晶格(Hyperfine aperiodic optical superlattice, HAOS)上達成光波長的三倍頻轉換，且HAOS在轉換效率以及可達成波長的自由度上皆優於過往之串接式週期性准相位匹配光柵(Sequentially periodic, SP)。此外我們亦討論了數種現有以准相位匹配技術達成三倍頻轉換的方法，以及在製程上誤差問題所造成的影響。最後我們提出了一種三段式結構，其在轉換效率上可超越過去以兩段週期性一階准相位匹配光柵串接所得之最高轉效率。

In the thesis, we proposed and experimentally demonstrated an optimized hyperfine aperiodic optical superlattice (HAOS) for the third-harmonic generation (THG). The HAOS outperforms the sequentially periodic structure in the conversion efficiency and the degree of freedom of achievable wavelength. We also discussed the several schemes to achieve third-harmonic generation by QPM technique, and the practical issue in fabrication. Finally, a three-section structure is proposed to exceed the maximum THG efficiency obtained by sequentially periodic method with two first-order QPM gratings which has the highest THG efficiency to the best of our knowledge.

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