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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-22 1:23 |
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Conference: Bucharest University Faculty of Physics 2013 Meeting
Section: Optics, Spectroscopy, Plasma and Lasers
Title:
What is the Axial Resolution of Second Harmonic Imaging Microscopy?
Authors:
Iulian Ionita (1), Andreea Matei (2)
Affiliation:
1. University of Bucharest
2. National Institute for Laser, Plasma & Radiation Physics, Bucharest
E-mail
i_ionita@yahoo.com
Keywords:
Second harmonic generation
Microscopy
Resolution
Abstract:
Second-harmonic-generation (SHG) is a nonlinear second-order optical process occurring in systems without a center of symmetry and with a large molecular hyperpolarizability. SHG is a nonlinear source of contrast which arises directly from molecules arranged in ordered arrays. Short time after laser discovery SHG been used as a tool for characterizing surfaces and then was integrated into a microscope by imaging SHG signals from polycrystalline layers. Actually the SH Imaging Microscopy (SHIM) is relatively wide spread in biological research because it provides structural information especially from polarization properties. Concerning the spatial resolution it depends both on the microscope objective performances and on SHG mechanism. SHG is a process strongly dependent on the excitation power and a significant emission results from a small part of the focus volume (waist beam of the lens).
One of the bottle necks of SHIM is its spatial resolution. The spatial resolution is limited by the diffraction limit that is about the wavelength (several hundred nm) of the incident waves. In biological samples investigations was reported 1 micron.
The present communication reports the SHIM can be sensitive to a z-step of 100 nm on a regular and homogeneous sample which was deposit on silicon wafer in layers with different thickness.
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