1、NSOM 近場光學(xué),界面和倏逝場,透射和反射系數(shù),近場光學(xué),近場光學(xué)的歷史,1928 AD E. H. Synge ( England ),1973 AD Ash optical methods are disturbing the optical response).,xyz piezo,Feedback,Impedance detector,Electrodes,Piezo actuator,Aperture SNOM,Aperture SNOM,Illumination,Collection,Illumination collection,Reflection collection,Tr

2、ansmission illumination,Transmission collection,Operational modes,Typical set up,Aperture SNOM,Monochromator,SNOM tips,Aperture SNOM,Optical fiber,SNOM tips Calculation of the distribution of electric field as a function of the tip geometry,Aperture SNOM,Source: InAs Qdot Point like source l/40 belo

3、w the surface,SNOM tips - pulling,Aperture SNOM,Core,Cladding,Metal coating,SNOM tips - etching,Aperture SNOM,Core,Light propagation,Cladding,Metal coating,Holes are dug by various methods: The best results are obtained by FIB,NSOM 應(yīng)用的優(yōu)點(diǎn),與傳統(tǒng)光學(xué)顯微鏡比較,衍射極限的突破 大幅降低設(shè)備成本,理想透鏡可分辨的最小距離 D,D =,0.61,NA,：入射光波長

4、NA：透鏡的數(shù)值孔徑,與電子掃描式顯微鏡 ( AFM、STM)比較,非破壞性測量 可偵測到真實(shí)的表面 ( Real Surface Measurement ),樣品不需繁復(fù)的制備手續(xù),無需在真空下檢測,具有其他光學(xué)性質(zhì)的優(yōu)點(diǎn),應(yīng) 用,近場光學(xué)原理除了 應(yīng)用于近場光學(xué)顯微鏡、作為納米尺寸的局部光學(xué)強(qiáng)度與材料的光學(xué)特性等測量用外，由于此技術(shù)同時具有納米尺寸加工與曝光的能力，故還可用于制作單電子晶體管、量子阱等納米元件，以及應(yīng)用于更高密度的存儲器上。,optical quantum corral,Aperture SNOM,The experiment: Testing the subwavelke

5、nght modulation induced on the local density of states of the optical modes by the fabrication of nanometric opticla corrals Substrate ITO Modulators 100nm100nm50nm gold particles deposited by e-beam lithography,To test the real LDOS the tip should act as a perfetct dipole at a nanometric distance f

6、rom the surface. Real tips always pertirb the LDOS and what is measured is the combined LDOS of the sample and the tip!,optical quantum corral,Light Polarization control Elliptical mirros that selects only the near field radiation (propagating radiation is not allowed in the “forbidden light region with qqc The signal is 0 only closo to the sample,optical quantum corral,Teorical optical LDOS in x, y and z direction,optical quantum corral,Near field results in trasmission. Best results obtained with a gold coated tip without apertures (the tip At the tip the polari