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2Two-dimensional metalenses for creation of portable biosensors of
single molecules
A. Barulin1'2*' S. Novikov1, A. Chernov1'3
1- Center for Photonics and 2D Materials, Moscow Institute of Physics and Technology, Dolgoprudny 141700,
Russia
2- Department of Biophysics, Institute of Quantum Biophysics, Sungkyunkwan University, Suwon, 16419,
Republic of Korea 3- Russian Quantum Center, Moscow 121205, Russia
Dielectric metalenses can focus light with the spatial resolution of the diffraction limit with sufficient control over the numerical aperture, size, and chromatic aberration correction. Due to micrometer-size thickness, this nanophotonic structure appears a compact planar analogue of refractive optical elements. Metalenses find their applications in multi-functional and miniaturized high aperture optical devices for visualizing biological objects, however, detection of single-molecule fluorescence, which is a key element in molecular biology and medicine, requires the use of high-quality and costly optical and optoelectronic components with high collection efficiency of fluorescence photons. We present a metalens made of nanofins of amorphous silicon, which has high numerical aperture and focusing power [1]. This metalens is capable of detecting single fluorescent Alexa647 molecules using fluorescence correlation spectroscopy, and is also capable of determining the size of fluorescent nanoparticles with nanometer accuracy. The demonstrated optical device greatly reduces the size of the refractive lens and practically does not lose the efficiency of collecting photons at the same values of the numerical aperture. The proposed nanophotonic platform will make it possible to create compact and portable fluorescent biosensors for medicine and point-of-care diagnostics and for screening environmental pollution.
The research received financial support from the Ministry of Science and Higher Education of the Russian Federation (Agreement № 075-15-2024-622) and from the Priority 2030 program.
[1] A. Barulin, et al, Dual-wavelength metalens enables Epi-fluorescence detection from single molecules, Nature Communications 15, 26
(2024).
