Recent years have seen explosive growth in the use of organic materials, composites, or organics bound to an inorganic substrate, to solve engineering problems that traditionally were approached only with inorganics. The remarkable speed with which these new technologies are appearing is contrasted by the remarkable scarcity of non-destructive, invitro, and in-vivo techniques for characterizing the biophysical, chemical, and mechanical properties of these often delicate and nano-structured materials. Near-field scanning optical microscopy (NSOM) for quantitative evaluation of surfaces is a practical solution for this type of evaluation.
Traditional spectroscopy methods utilize 'far-field' light easily propagated through long distances.
However, far field light is subject to diffraction effects, whether mirrors or lenses are used. Diffraction effects limit the amount of 'focus' that can be achieved, thus the spatial resolution for traditional microspectroscopy systems is limited to the wavelengths used; i.e. 10 microns for IR, ~1 micron for visible wavelengths.
Thorlabs' F-Theta lens features an air-spaced, 3 element design with a 100 mm focal length. The elements are coated with a high efficiency AR coating for a 1064 nm Nd:YAG laser and for a visible...
Topics of Interest
Diffraction and imaging are central topics in many modern and scientific
fields. Fourier analysis and sythesis techniques are a unifying theme
throughout this subject matter. For example,...
It is well known that sound travels around corners and aroundobstacles. Music reproduced in one room of a home can be heard down the hall and in other rooms. Diffraction is one of the mechanisms...
M. M. Alkaisi,
MacDiarmid Institute of Advanced Materials and Nanotechnology, University of Canterbury
R. J. Blaikie,
MacDiarmid Institute of Advanced Materials and...
5.5 Evaluation of the Conventional Near-Field to Far-Field Transform
In Chapter 4 (Section 4.19) a general overview of the conventional manipulation of data to obtain asymptotic far-field parameters...
charge coupled device