Super-resolution imaging using nano-bells

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Our group has demonstrated a new scheme for optical super-resolution, inspired, in-part, by PALM and STORM. Here each object in the field of view is tagged with a signal that allows them to be detected separately. By doing this we can identify and locate each object separately with significantly higher resolution than the diffraction limit. We demonstrated this by imaging nanoparticles significantly smaller than the optical resolution limit. In this case the "tag" we have used is the frequency of vibration of nanoscale "bells" made of metallic nanoparticles whose acoustic vibrational frequency is in the multi-GHz range. Since the vibration of the particles can be easily excited and detected and the frequency is directly related to the particle size, we can separate the signals from many particles of sufficiently different sizes even though they are smaller than, and separated by less than, the optical resolution limit. Using this scheme we have been able to localise the nanoparticle position with a precision of ~3nm. This has many potential advantages - such nanoparticles are easily inserted into cells and well tolerated, the particles do not bleach and can be produced easily with very dispersed sizes. We estimate that 50 or more different particles (or frequency channels) can be accessed in each optical point spread function using the vibrational frequencies of gold nanospheres. However, many more channels may be accessed using more complex structures (such as nanorods) and detection techniques (for instance using polarization or wavelength selective detection) opening up this technique as a generalized method of achieving super-optical resolution imaging.

How nano-bells work

How nano-bells work. (a) Shows a representation of an optical image of metallic particles where the particles cannot be resolved. (b) Shows a representation of an acoustic amplitude image of the same particles at a single frequency F1 and F2. (c) Localisation of the particles from the centroids of the PSF of each frequency. The centroids obtained at frequencies F1 and F2 lead to the localisation of the particles with greater precision than the optical system used to image them. The size is obtained by the vibrational frequency of each particle.

Related Publications and Talks


Super-resolution imaging using nano-bells. Rafael Fuentes-Dominguez et al, Scientific Reports, 8(1):16373, 2018.


Super-resolution imaging using nano-bells. Rafael Fuentes-Dominguez. LU Nottingham UK (2018). Oral presentation.