TITLE:
Scanning Head for the Apertureless near Field Optical Microscope
AUTHORS:
D. V. Kazantsev, H. Ryssel
KEYWORDS:
Near-Field Optics; Apertureless SNOM; Scanning Head
JOURNAL NAME:
Modern Instrumentation,
Vol.2 No.2,
April
30,
2013
ABSTRACT: The design and characterization of a tip control unit
for an apertureless scanning near field optical microscope (ASNOM) is
reported. To make the instrument operation easier, the cantilever control parts
(piezo excitation of the cantilever vibration for the dynamic mode feedback
and the parts necessary for the optical lever scheme of the vibration control)
were placed in a separate detachable assembly. To suppress the influence of
vibrations of the setup, the assembly was made lightweight. Good optical access
to the ASNOM tip from various directions is provided in the system. High
long-term mechanical stability of the system (~50 nm lateral drift in 18 hours)
as well as low sensitivity to seismic vibrations (~400 pm
RMS) is demonstrated. It is shown that external sound is not a main source of
noise in the topography image (~200 pm RMS). The light field distribution
(with its amplitude and phase) around the ASNOM tip was acquired
by scanning the focal spot around the tip, and a high optical quality of the
system is demonstrated.