NSOM is an optical imaging technique which allows for high resolution imaging below the diffraction limit. In Transmission mode NSOM the light from the NSOM probe is transmitted through the sample and collected below. It is an ideal method for looking at transparent or semi-transparent samples, for example cells or absorption studies. In addition NSOM can operate in liquid without any scattering allowing imaging of live cells. It is an easy and powerful technique to implement for high resolution optical imaging on a wide variety of samples.
Key Features
-
The only technique allowing localized illumination without out-of-focus light which is impossible in Confocal, PALM\STORM or STED.
-
Ideal for substrates in liquid mediums where far field illumination is difficult.
-
Resolutions of up to 50 nm's Ideal for transparent or semi-transparent samples
-
Ideal for cells even in liquid Ideal for absorption studies
-
Localized illumination with no out-of-focus light
Exemplary Paper
Nonradiating Anapole Modes in Dielectric Nanoparticles
Miroshnichenko, A. E., Evlyukhin, A. B., Yu, Y. F., Bakker, R. M., Chipouline, A., Kuznetsov, A. I., … Kivshar, Y. S. (2015). Nonradiating anapole modes in dielectric nanoparticles. Nature Communications, 6, 8069.
Near field characterization was done on a sample of dielectric nanoparticles with a CryoView MP by illuminating the sample with a super continuum source with the transmitted light being collected in the near-field. Spectral overlap of the toroidal and electric dipole modes were achieved through tuning of the geometry. A highly pronounced dip in the far-field scattering accompanied by the specific near-field distribution associated with the anapole mode was observed confirming the interference of two different dipole moments. Such radiationless excitation can make the nanodisk almost invisible in the far-field at the anapole’s excitation wavelength. The anapole mode offers a new way to achieve an invisibility condition for lossless dielectric nanostructures based on the cancellation of radiation scattering.
Link to abstractYuri S. Kivshar is a distinguished professor and head of Nonlinear Physics Centre of The Australian National University (ANU), and The International Research Centre for Nanophotonics and Metamaterials.
Exciting Applications
-
Study ion transport into membranes by using a Calcium sensitive dye and locally illuminating on a desired location on the membrane with no background light.
-
Study absorption properties of different materials or live organisms.
-
Study IR absorption in micron resolution by introducing IR light via an apertured NSOM probe.
