一般遠場光學顯微技術受限於光學繞射極限(diffraction limit)，於軸向與側向空間解析度均無法達到奈米等級。雖然孔徑式近場掃描式光學顯微鏡(near-field scanning optical microscope，NSOM) 可突破光學繞射極限，但解析度仍侷限在50nm左右，因此本論文以商用之原子力顯微鏡（atomic force microscope，AFM)為基礎，發展一無孔式近場掃描式光學顯微鏡(apertureless near-field scanning optical microscopy，aNSOM)，企圖將空間解析度提升到10nm以下。
為了多元化的應用，此系統可支援下打下收、側打側收和下打側收三種模式。並利用自行發展之控制器與電路設計來對探針震盪的高階倍頻項(high harmonics terms)進行解調、以量測各種樣品的近場影像，接著搭配文獻的理論做一分析與討論。此外，又加入外差干涉式光學訊號擷取機制，以期能進一步提升近場訊號的訊噪比(signal-to-noise ratio，SNR)，而得到一清晰的奈米級影像。最後，利用此aNSOM對奈米狹縫所產生的表面電漿子作量測。搭配有限時域差分法(finite difference time domain，FDTD)的理論模擬，證實了實驗上利用調控入射光的偏振模態，將可改變近場之場強分佈的結果。

Due to the restriction of the diffraction limit in conventional optical microscopes, the axial and lateral spatial resolutions are hard to be achieved to a nanometer scale. Although an aperture near-field scanning optical microscope (NSOM) has been developed for breaking the diffraction limit, the spatial resolution is still limited in the range of 50nm. In this thesis, an apertureless near-field scanning optical microscope (aNSOM) based on a commercial atomic force microscope (AFM) has been developed to attempt to achieve spatial resolution better than 10 nm.
In order to provide various applications, the incident and emitted light can be supplied and collected, respectively, both from the bottom or the side of the sample. The optical signal with high harmonic terms scatted by the vibrated tip is demodulated by using a home-made controller and circuit boards. In addition, the heterodyne interferometric detection technique has been introduced to improve the signal-to-noise ratio (SNR) for acquiring clear nanometer-scale images.
Finally, the surface plasmons from nanoslits has been studied by utilizing the aNSOM. Furthermore, the experimental results of the polarization-dependence of near-field signal have been proved and are consistent with the simulation by finite difference time domain (FDTD) method.

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