Last time we discussed the physics behind the polaritonic lensing mechanism that can be used to beat the diffraction limit. Hexagonal Boron Nitride crystals can use these polaritons to limit-destructive interference by linearly propagating polaritons along their positive permittivity axis. Boron Nitride is famous for having a birefringent crystal configuration: one axis of the crystal has a positive permittivity and easily conducts polaritons, while the orthogonal axis has a negative permittivity and reflects light away. The presence of both these permittivities in the same crystal allows Boron-Nitride to have superlensing applications by coupling decaying light rays into polaritons and retaining image information that is normally lost.
Viewing entries tagged
Hyperbolic nanomaterials have recently attracted interest due to the alternative lensing mechanism that their unique crystal structure can accommodate. This lensing technique uses a subatomic particle called a phonon-polariton to capture evanescent light rays before they decay1. Using polaritons allows this lensing mechanism to retain resolution that is normally lost in traditional lenses, producing a high resolution lens known as a super-lens2.
For centuries, scientists have been studying methods to overcome the diffraction limit of light. Currently, most optical instruments use traditional, photon-based lenses that magnify objects by refracting light. These lenses are diffraction limited--that is, their maximum magnification is restricted to half a wavelength of light. It is anticipated that the introduction of non-diffraction limited optics to molecular biology can have the same revolutionary effect that optical microscopy had on the field.