Subnanomolar fluorescent-molecule sensing by guided resonances on nanoimprinted silicon-on-insulator substrates

Abstract

We have produced nanoimprinted silicon-on-insulator (SOI) substrates with high precision and applied them for fluorescence (FL) enhancement of typical dye molecules of Rhodamine series. We experimentally found that the FL signals on the nanoimprinted SOI substrates are enhanced by more than 200 fold as compared with the signals on Si wafers. The FL enhancement mechanism was investigated using spectroscopic and theoretical approaches. The results indicated that guided resonances with large density of states significantly contribute to the FL enhancement. We also substantiated that the FL-enhancing substrates well serve as rapid-sensing platforms for a very dilute FL-molecule solution with subnanomolar concentration. The nanoimprinted SOI substrates were repeatedly reused without degradation.

Overcoming metal-induced fluorescence quenching on plasmo-photonic metasurfaces coated by a self-assembled monolayer

“…S6 (ESI †), consistent with previous results. 30 Thus, the SAM plays a key role in the large FL enhancement on the SC metasurfaces. The FL EF on R590 was also examined for Si photonic crystal slabs using the common substrate and found to be over 200-fold.…”

All-Dielectric Metasurfaces with High-Fluorescence-Enhancing Capability

“…We mention the reasons why we chose SOI substrates in this study. One is practical; we employed SOI substrates in the previous experiments [29,[48][49][50], and therefore, could use them at once. The other is that we preferred the relatively smaller optical loss in crystalline SOI than in amorphous Si films grown on transparent substrates such as SiO 2 .…”

“…To the best of our knowledge, there are no published reports on highly FL-enhancing dielectric metasurfaces in FL-molecule sparsely dispersed configurations. However, it was reported that photonic crystal slabs enabled hundred-fold FL enhancement [50], and that wavelength-selective photoluminescence (PL) extraction from semiconductor quantum dots (QDs) can be very effective in a dielectric metasurface [51]; thus, an opportunity exists to explore highly FL-enhancing dielectric metasurfaces. Here, we aim at examining Si-rod-array metasurfaces in terms of FL enhancement.…”

Ultraviolet-nanoimprinted packaged metasurface thermal emitters for infrared CO2sensing

“…We used a micropattern imprinting machine (ST50, Toshiba Machine) for UV–NIL [18, 19]. On a 30 mm square 1 mm thick quartz mold, 250 nm high rectangular mesas corresponding to the Au patches are arrayed.…”