Upconversion amplification through dielectric superlensing modulation

Abstract

Achieving efficient photon upconversion under low irradiance is not only a fundamental challenge but also central to numerous advanced applications spanning from photovoltaics to biophotonics. However, to date, almost all approaches for upconversion luminescence intensification require stringent controls over numerous factors such as composition and size of nanophosphors. Here, we report the utilization of dielectric microbeads to significantly enhance the photon upconversion processes in lanthanide-doped nanocrystals. By modulating the wavefront of both excitation and emission fields through dielectric superlensing effects, luminescence amplification up to 5 orders of magnitude can be achieved. This design delineates a general strategy to converge a low-power incident light beam into a photonic hotspot of high field intensity, while simultaneously enabling collimation of highly divergent emission for far-field accumulation. The dielectric superlensing-mediated strategy may provide a major step forward in facilitating photon upconversion processes toward practical applications in the fields of photobiology, energy conversion, and optogenetics.

Huge upconversion luminescence enhancement by a cascade optical field modulation strategy facilitating selective multispectral narrow-band near-infrared photodetection

“…As revealed in Fig. 2f , after Au NRs are assembled, their LSPRs are broadened owing to the plasmonic coupling among Au NRs and overlap with the absorptions of Nd 3+ at 808 nm, Yb 3+ at 980 nm, and Er 3+ at 1540 nm 26 .…”

“…In the past, a few approaches have been explored to boost UCL and decrease the pumping threshold of UCNCs, e.g., nanocrystal surface passivation, photonic crystal engineering, plasmon/organic antennas, and superlensing effects 19 , 20 . Among other techniques, utilizing the localized surface plasmon resonance (LSPR) of noble-metal nanostructures and the superlensing effect of dielectric optical microstructures can serve as two efficient strategies to take advantage of the highly nonlinear response of UCNCs to excitation intensity 21 – 26 . Although significant UCL enhancements (up to four orders of magnitude in some extreme cases) can potentially be achieved by using these optical amplifiers 27 , the UCL enhancement is strictly limited by localization of the hotspot induced in the light field, which is typically much smaller than the dimensions of the UCNCs.…”

Optical Nanomaterials and Enabling Technologies for High‐Security‐Level Anticounterfeiting

“…Right: Photographic images, taken upon an incoherent light source illumination, of an encrypted quick response code with the use of the composite sheet. Reproduced with permission . Copyright 2019, Springer Nature.…”

Activating Antitumor Immunity and Antimetastatic Effect Through Polydopamine‐Encapsulated Core–Shell Upconversion Nanoparticles

“…Owing to their outstanding properties, upconversion nanoparticles (UCNPs) have found critical applications in a variety of biomedical fields, including multimodal imaging, controllable drug delivery, deep‐tissue optogenetics, and localized PDT . PDT can induce immunogenic cell death and activate an adaptive immune response against tumor‐associated antigens .…”