May 9, 2005 SZFKI-MFA Carbon Nanotube Learning Seminar 1 Electron-energy loss spectroscopy in carbon nanotubes: low energy Kamarás KatalinMTA SZFKI Thanks to: Thomas Pichler, Dresden

May 9, 2005SZFKI-MFA Carbon Nanotube Learning Seminar 2 Plasmons are longitudinal oscillations of an electron gas which can not be excited by the electric field of light at normal incidence They occur whenever and can be detected by the loss of energy of an electron beam (EELS) Plasmons T. Pichler, M.Knupfer, M.S. Golden, J. Fink, A.G. Rinzler, R.E. Smalley: Phys. Rev. Lett. 80, 4729 (1998) EELS measures the loss function: Results of the Dresden group are measured in transmission on extremely thin (~100 nm) samples KK analysis  1,  2

May 9, 2005SZFKI-MFA Carbon Nanotube Learning Seminar 3 Optical and energy-loss spectra The peak in EELS (the loss function ) occurs at higher energy than the maximum in optical absorption X. Liu, T. Pichler, M. Knupfer, M.S. Golden, J. Fink, H. Kataura, Y. Achiba: Phys. Rev. B 66, (2002) electron collective resonance andtransitions TO LO

May 9, 2005SZFKI-MFA Carbon Nanotube Learning Seminar 4 VIS-UV spectra of nanotubes - “plasmon peaks” X. Liu, T. Pichler, M. Knupfer, M.S. Golden, J. Fink, H. Kataura, Y. Achiba: Phys. Rev. B 66, (2002)

May 9, 2005SZFKI-MFA Carbon Nanotube Learning Seminar 5 and transitions show much broader dispersion than transitions between van Hove singularities Dispersion in EELS of nanotubes T. Pichler, M.Knupfer, M.S. Golden, J.Fink, A.G. Rinzler, R.E. Smalley: Phys. Rev. Lett. 80, 4729 (1998) Polarization (TO, predicted): dispersive peaks: parallel to tube axis molecular peaks: perpendicular to tubes We know now that this is not right due to the antenna effect!

May 9, 2005SZFKI-MFA Carbon Nanotube Learning Seminar 6 STEM (scanning transmission electron microscope) /EELS measurements on individual samples B.W. Reed, M. Sarikaya: PRB 64, (2001) Spectra could be taken of bundles and individual tubes, in penetrating mode (bulk plasmons) and “aloof mode” (surface plasmons)

May 9, 2005SZFKI-MFA Carbon Nanotube Learning Seminar 7 What next? Contents: History of Near-field Optics Non-radiating Sources and Non-propagating Fields Evanescent Optics Theories and Modellings Inverse Problem and Apparatus Function Criteria of Quality, Noise and Artifacts Nano-collectors and Nano-emitters Instrumentation Main Near-field Microscope Configurations Near-field Image Processing Applications of Near-field Microscopy Appendix A: Basis of Optics Readership: Optical researchers and engineers, as well as graduates keen on peculiar optical phenomena. 340pp Pub. date: Mar 2003 NEAR-FIELD MICROSCOPY AND NEAR-FIELD OPTICS by Daniel Courjon (Université de Franche-Comté, France)