A near-field scanning optical microscope with a high Q -factor piezoelectric sensing element
1999; American Institute of Physics; Volume: 75; Issue: 12 Linguagem: Inglês
10.1063/1.124823
ISSN1520-8842
AutoresD. N. Davydov, Konstantin B. Shelimov, Thomas Haslett, Martin Moskovits,
Tópico(s)Force Microscopy Techniques and Applications
ResumoA tapping-mode near-field scanning optical microscope utilizing a piezoelectric microtuning fork as its height-sensing element is described. We have developed a method for modifying and attaching an optical fiber to the tuning fork that allows the assembly to retain a Q factor of up to 9000, substantially higher than the Q factors described so far in the literature for tuning-fork-based instruments. The method involves reducing the diameter of the cladding of the optical fiber down to 17–25 μm using several chemical etching steps, before the fiber is attached to the tuning fork. A sharp upturn in the Q factor is observed when the fiber diameter d drops below ∼25 μm. An analysis showing that the stretching force constant of a bent fiber is proportional to d4 accounts for the great sensitivity of the Q factor to the fiber diameter. The high Q factors result in improved force sensitivity and allow us to construct a tapping-mode instrument without the use of additional dithering piezoelements.
Referência(s)