Near-field optical microscopy study of metal micro- and nano-slits

• Main Authors: Ming-Hui Tseng, 曾名輝
• Other Authors: Heh-Nan Lin
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/68845228415337561108

碩士 === 國立清華大學 === 材料科學工程學系 === 94 === We successfully fabricate gold-coated optical fiber probes with apertures of around 60 ~ 150 nm and corresponding relative optical throughputs of 10-9 ~ 10-3. The correspondence between the relative optical throughputs and the aperture diameters carefully determined by scanning electron microscopy has been found quite consistent. As a result, the relative optical throughput of a fiber probe can be used conveniently for the determination of the aperture size. The atomic force microscopy nanomachining technique developed in our lab is used to fabricate samples with metal slits of tens to hundreds of nanometers. Optical lithography is also used to fabricate samples with multiple metal slits of 2 μm and 10 μm. Finally, the near-field optical images of the prepared samples illuminated by a 532 nm green laser are obtained by using a near-field scanning optical microscope. The serial analysis of the metal slits contributes a lot to the applications for the near- field optical bio-scanner and the metal mask in the lithography technique. The results show that the optical interference phenomenon analogous to the single-slit diffraction can be observed when the size of the nano-slit is approximately or a little wider than the wavelength of the incident optical wave. And the distance between the bright lines is about 1.8 μm. Whereas the phenomenon can’t be observed when the size of the nano-slit is narrower than half of the wavelength of the incident optical wave. And the periodic optical interference fringe can be observed after the incident optical wave passed through the structure of 2 μm wide multiple slits. And the distance between the bright lines is about 1.74 μm.