A Refractive Index Sensor Based on High Quality Factor All-Dielectric Metasurface and Its Application

Abstract

The invention discloses a refractive index sensor based on a high quality factor all-dielectric metasurface, which includes a transparent substrate and a metasurface structure distributed on the surface of the transparent substrate in a periodic array. The metasurface structure adopts all-dielectric materials and is a subsurface wavelength thickness. The invention has no metal structure, no ohmic loss, no biological toxicity, and will not affect the activity of the object to be tested. Moreover, the metasurface structure is used, and the action area is short, which is expected to achieve high-speed response. In addition, the present invention is based on dielectric materials, such as semiconductor materials, which is beneficial to the realization of CMOS integration in the future. Not only that, the design theory can be extended to other wavebands, such as the terahertz waveband, using high-refractive-index, low-loss dielectric metasurface structures to detect refractive index or biomolecular fingerprints in different working wavebands.

Description

technical field [0001] The invention belongs to the field of optical sensing, in particular to a refractive index sensor based on a high quality factor all-dielectric metasurface and its application. Background technique [0002] The use of optical resonance-based micro-nano structures to realize simple and high-sensitivity refractive index sensing has very important application value. Especially in the detection of biomolecules, this method avoids the complicated operation of using fluorescent dyes to label the biomolecules to be tested, and directly measures the small changes in the refractive index of the solution caused by the introduction of the molecules to be tested. A smaller detection limit of the refractive index means that a lower concentration of molecules can be detected with high sensitivity. [0003] Typical optical resonant devices used for refractive index sensing include waveguide or optical fiber structures based on microfluidic technology. Although such ...

AI Technical Summary

Problems solved by technology

The use of metal structures has several limitations: one is that ohmic losses in the metal structure make it difficult to obtain a high quality factor optical response (wider resonance peak bandwidth), which affects the detection limit / sensitivity; the other is that metal The structure is not conducive to integration with the existing CMOS process, and the metal has certain biological toxicity, which is not conducive to the application of biomolecular detection

However, the currently used two-dimensional grating structures of high refractive index media (for example, silicon disk structures) are all based on a single resonance mode, with a low degree of control freedom; and due to material loss, none of them can achieve resonance with a high quality factor below a wavelength of 1 μm. characteristics, which greatly limits its effective operating bandwidth and the further reduction of device size

[0005] To sum up, there is currently no convenient and safe solution to realize a highly sensitive refractive index sensor based on an all-dielectric metasurface structure in the wavelength band below 1 μm.

Images