Publications by authors named "N Bokor"

We introduce a simple, compact two-mirror system for diffuse light concentration. The design principle is based on local conservation of optical brightness. The system design is flexible, and we are able to compute mirror shapes given arbitrary incident beam direction and target cross-sectional shape.

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We propose a new design principle for optimal concentration of light with small diffusivity based on the conservation of local brightness in passive optical transformations. A coordinate transformation is applied on the incoming rays to compensate for the variations in local brightness by the focusing stage. We apply this analytic design for a compact reflective configuration for ideal imaging concentration of diffuse light such as sunlight in one dimension on an elongated target with arbitrary cross-sectional shape at the thermodynamic limit.

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We fabricated a resolution target for super-resolution microscopes (SRMs). The target was constructed by scattering a dyed photo-resist on a glass cover plate and used UV nano-imprinting to transfer minute line-and-space patterns on to the photo-resist layer. Using this resolution target, an image obtained from a SRM and its properties was evaluated quantitatively.

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We fabricate a two-color annular hybrid wave plate (TAHWP) for fluorescence depletion super-resolution microscopy by combining quartz plates. Inserting the TAHWP into a commercial laser-scanning microscope together with a quarter-wave plate creates a three-dimensional spherical fluorescence spot smaller than the diffraction limit. Since a simple experimental setup easily provides a spot with a volume of ∼100  nm, the TAHWP can improve the performance of various microspectroscopic devices.

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In super-resolution microscopy based on fluorescence depletion, the two-color phase plate (TPP) is an indispensable optical element, which can independently control the phase shifts for two beams of different color, i.e., the pump and erase beams.

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