Fabrication of refractive index sensors using polarization independent metamaterial and their application to chemical concentration measurement and DNA detection

Abstract

Biochemical sensors are used for discrimination of biochemical species, concentration measurement, and so on. Because metamaterial responds to slight changes in the ambient refractive index, it is possible to realize ultrasensitive biochemical sensors. We designed and fabricated refractive index sensors using polarization independent metamaterial and examined their application as biochemical sensors. Refractive index sensitivity, concentration measurement, and DNA detection were carried out.

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“…Next, the target DNA with a completely complementary sequence to the sensor DNA was added and washed with pure water, and then, the reflection spectrum in a dry state was measured. Figure 11 shows a comparison of reflection spectra before and after DNA binding [119]. As shown in the figure, it was confirmed that the reflection peak of the metamaterial was shifted by 8.5 nm due to the binding of the target DNA, and the DNA could be detected.…”

“…However, the refractive index sensitivity is inferior to that of the refractive index sensor [135] reported by Lee et al In recent years, the author has designed and fabricated a localized surface plasmon-type refractive index sensor using a polarization-independent metamaterial with the aim of realizing a compact and highly sensitive biochemical sensor [116,119]. Figure 10 shows an SEM photograph of the metamaterial fabricated by the author [119]. Au cut wire structures are formed rotationally symmetrically on a quartz substrate.…”

“…In other words, metamaterials are artificial transcendental materials. It is attracting attention as an innovative artificial material that exhibits behavior not found in natural substances and can realize a negative refractive index [94–120]. The unit structures (meta‐atoms/metamolecules) that make up a metamaterial are smaller than the light wavelength and are dispersed or periodically arranged in space and behave as an effective refractive index medium.…”

“…In recent years, the author has designed and fabricated a localized surface plasmon‐type refractive index sensor using a polarization‐independent metamaterial with the aim of realizing a compact and highly sensitive biochemical sensor [116,119]. Figure 10 shows an SEM photograph of the metamaterial fabricated by the author [119].…”