caa a22 4500 463213823 CHVBK 20180405153150.0 cr unu---uuuuu 170326e20071101xx s 000 0 eng 10.1007/s00339-007-4114-6 doi (NATIONALLICENCE)springer-10.1007/s00339-007-4114-6 Optical near-field distribution in an asymmetrically illuminated tip-sample system for laser/STM nanopatterning [Elektronische Daten] [Z.B. Wang, B.S. Luk'yanchuk, L. Li, P.L. Crouse, Z. Liu, G. Dearden, K.G. Watkins] In surface nano-patterning using an atomic force microscope (AFM) tip in scanning tunnelling microscopy (STM) mode and illuminated by a laser, two controversial physical mechanisms exist in the literature: the field-enhancement (FE) model and the thermal-induced mechanical contact (TMC) model. Due to the presence of evanescent waves in the optical near-field, the exact calculation of the field distribution of the tip-sample system in micro/nano scales becomes complicated. There is a lack of understanding of the asymmetrically illuminated tip-sample system. In this paper, full 3D finite-difference time-domain (FDTD) analysis was carried out to investigate the field distribution in different tip-sample systems. The effects of different tip/sample materials (either dielectric or plasmonic material), the gap distance, and laser incidence angles on the field distribution/enhancement have been studied. For the first time, we have demonstrated two new effects which are helpful in distinguishing the controversial mechanisms: (1) on the sample surface, the field peak position has a shift away from the tip-axis at large angles of incidence, and (2) the field enhancement could depend strongly on the horizontal component (perpendicular to tip-axis) of the incident wave instead of the vertical component (along tip-axis). The optimal incident angle is around 30° for the maximum field under the tip. The existence of field-distribution nodes on the 3D tip surface that leads to the in-homogenous heating of the tip is also predicted. Springer-Verlag, 2007 Wang Z.B. Laser Processing Research Centre, School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Sackville Street, M60 1QD, Manchester, UK aut Luk'yanchuk B.S. Data Storage Institute, DSI Building, 5 Engineering Drive 1, 117608, Singapore, Singapore aut Li L. Laser Processing Research Centre, School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Sackville Street, M60 1QD, Manchester, UK aut Crouse P.L. Laser Processing Research Centre, School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Sackville Street, M60 1QD, Manchester, UK aut Liu Z. Corrosion and Protection Centre, School of Materials, University of Manchester, The Mill, M60 1QD, Manchester, UK aut Dearden G. Laser Group, Department of Engineering, University of Liverpool, Brownlow Street, L69 3GH, Liverpool, UK aut Watkins K.G. Laser Group, Department of Engineering, University of Liverpool, Brownlow Street, L69 3GH, Liverpool, UK aut Applied Physics A Springer-Verlag 89/2(2007-11-01), 363-368 0947-8396 89:2<363 2007 89 339 https://doi.org/10.1007/s00339-007-4114-6 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00339-007-4114-6 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Wang Z.B. Laser Processing Research Centre, School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Sackville Street, M60 1QD, Manchester, UK aut NATIONALLICENCE 700 1- Luk'yanchuk B.S. Data Storage Institute, DSI Building, 5 Engineering Drive 1, 117608, Singapore, Singapore aut NATIONALLICENCE 700 1- Li L. Laser Processing Research Centre, School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Sackville Street, M60 1QD, Manchester, UK aut NATIONALLICENCE 700 1- Crouse P.L. Laser Processing Research Centre, School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Sackville Street, M60 1QD, Manchester, UK aut NATIONALLICENCE 700 1- Liu Z. Corrosion and Protection Centre, School of Materials, University of Manchester, The Mill, M60 1QD, Manchester, UK aut NATIONALLICENCE 700 1- Dearden G. Laser Group, Department of Engineering, University of Liverpool, Brownlow Street, L69 3GH, Liverpool, UK aut NATIONALLICENCE 700 1- Watkins K.G. Laser Group, Department of Engineering, University of Liverpool, Brownlow Street, L69 3GH, Liverpool, UK aut NATIONALLICENCE 773 0- Applied Physics A Springer-Verlag 89/2(2007-11-01), 363-368 0947-8396 89:2<363 2007 89 339 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer