本論文利用受激輻射耗損顯微術(Stimulated emission depletion Microscopy, STED)中抑制放光的想法嘗試去抑制非螢光訊號，受激輻射耗損顯微術只能運用於螢光訊號，利用受激輻射耗損的方式去抑制點擴散函數周圍的螢光訊號進而取得超解析，然而此技術目前為止僅能運用於螢光訊號的調變，則造成此技術在使用上有了限制，為了改善該方面的限制，我們提出一個新的概念，嘗試用基態耗損(Ground state depletion, GSD)的方式去調控二倍頻或三倍頻等非螢光訊號的強度，則能使此技術的概念可用於非螢光訊號，從而拓展此技術的應用範圍。
從基態耗損會影響吸收，並利用材料本身因為有實際能階會增強倍頻與可進行基態耗損的特性去證實此概念的可能性，並自製出符合實驗需求的樣本 ，利用Z-scan的技術去量測出樣本的非線性係數與導入耗損光下吸收的變化，並利用倍頻會在介面放光的特性去驗證實際抑制三倍頻放光與Z-scan所量測的數值模擬倍頻放光是否相符合，最後模擬此概念藉由激發受激耗損顯微術系統時有機會達到69nm或更小的的解析度。 ;This thesis aims to suppress third harmonic generation (THG) signals through ground state depletion (GSD) based on the concept of stimulated emission depletion in STED microscopy. The STED microscopy is based on fluorescent signals. By depleting the fluorescence signals, it modulates the point spread function (PSF) of fluorescence signals to reach super resolution. However, the applications of STED are limited by the using of fluorescence signals. To overcome this limitation, we propose a new concept to modulate the PSF of THG signals through GSD to improve the resolution of THG microscopy.
To prove this idea, we illustrate that the material absorption can enhance the THG signals and can be suppressed through ground state depletion. Proper sample of is made and its nonlinear coefficient is measured by both Z-scan technique and interface THG signals measurement. Combined with depletion light, the two-photon absorption coefficient is proved to be suppress through GSD, while the THG at interface is shown to decline with increasing depletion light intensity. Finally, applying the measured nonlinear coefficients to resolution simulation, the results indicate the resolution of THG microscopy can reach 69 nm or smaller based on GSD.
