研究原子裡的對稱性破壞是檢驗標準模型和探討弱作用力的有效方法，進而從中發現新物理。其主要表現在弱作用力裡的宇稱不守恆（parity non-conservation, PNC）現象上，而鉈是研究PNC重要的元素之一。 在作鉈原子束的冷卻以增加光譜精準度或者量測鉈原子裡某些禁止躍遷中的宇稱不守恆現象等實驗中，535 nm(6P3/2-->7S1/2) 都是作鉈原子相關實驗中很重要的光源。本論文主要工作為發展產生535 nm的染料雷射，然後加上377 nm光源，藉由觀察螢光光譜，研究當兩個光場同時存在於Λ型三能階時所發生的交互作用，包含基態與準穩態之間因破壞性干涉而有的電磁波引發透明(EIT)現象。 此實驗所選擇的三能階為包含超精細結構後鉈原子裡最靠近基態的Λ型三能階(6P1/2F=1、6P3/2F=1和7S1/2F=0)，其中6P1/2和6P3/2之間為禁止躍遷，且鉈原子束彼此之間碰撞機率極小，此結構幾近為理想Λ型三能階；此實驗可作為未來雷射冷卻Tl以及作PNC研究的初步。 我們在固定probe laser頻率下作coupling laser掃頻時的實驗結果證明了看見兩個光場同時於此系統中作用時產生的干涉現象。

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