[Paper Review] Dual-band polarized upconversion photoluminescence enhanced by resonant dielectric metasurfaces

Ziwei Feng, Tan Shi+5 more|arXiv (Cornell University)|May 16, 2023

Luminescence and Fluorescent MaterialsMaterials Science3 citations

TL;DR

This paper presents a resonant dielectric metasurface that enhances dual-band polarized upconversion photoluminescence in lanthanide-doped nanoparticles by exciting high-quality factor modes at 540 nm and 660 nm, achieving up to two orders of magnitude emission enhancement and polarization degrees of 0.86 and 0.91, respectively, enabling cross-polarization control for ultrabright, polarized light sources.

ABSTRACT

Lanthanide-doped upconversion nanoparticles emerged recently as an attractive material platform underpinning a broad range of innovative applications such as optical cryptography, luminescent probes, and lasing. However, the intricate 4f-associated electronic transition in upconversion nanoparticles leads only to a weak photoluminescence intensity and unpolarized emission, hindering many applications that demand ultrabright and polarized light sources. Here, we uncover a new strategy for achieving ultrabright and dual-band polarized upconversion photoluminescence. We employ resonant dielectric metasurfaces supporting high-quality resonant modes at dual upconversion bands enabling two-order-of-magnitude amplification of upconversion emissions. We demonstrate that dual-band resonances can be selectively switched on polarization, endowing cross-polarization controlled upconversion luminescence with ultra-high degrees of polarization, reaching approximately 0.86 and 0.91 at dual emission wavelengths of 540 nm and 660 nm, respectively. Our strategy offers an effective approach for enhancing photon upconversion processes paving the way toward efficient low-threshold polarization upconversion lasers.

Motivation & Objective

• To overcome the weak and unpolarized photoluminescence in lanthanide-doped upconversion nanoparticles, which limits their use in high-performance optical devices.
• To develop a strategy for achieving simultaneous dual-band emission enhancement with high polarization control.
• To enable selective switching of dual-band resonances via polarization control for tunable, bright, and polarized light sources.
• To demonstrate a platform for low-threshold polarization upconversion lasers using resonant dielectric metasurfaces.

Proposed method

• Design and fabrication of resonant dielectric metasurfaces with high-quality factor modes tuned to the two primary upconversion emission bands of 540 nm and 660 nm.
• Integration of lanthanide-doped upconversion nanoparticles with the metasurface to couple with localized resonant modes.
• Utilization of the metasurface's polarization-dependent resonant response to selectively excite and enhance emission at specific wavelengths.
• Employment of Mie resonances in high-index dielectric nanostructures to achieve strong field confinement and Purcell enhancement.
• Polarization-dependent excitation to enable cross-polarization control of the dual-band emission.
• Quantitative characterization of emission intensity enhancement and degree of polarization using angle-resolved and polarization-resolved photoluminescence spectroscopy.

Experimental results

Research questions

• RQ1 Can resonant dielectric metasurfaces simultaneously enhance upconversion emission at two distinct wavelengths?
• RQ2 Can the metasurface enable high polarization control over dual-band upconversion emission?
• RQ3 What level of emission intensity enhancement and polarization degree can be achieved using this approach?
• RQ4 Can the dual-band resonances be selectively switched on via polarization control?
• RQ5 Is this platform viable for enabling low-threshold polarization upconversion lasers?

Key findings

• The resonant dielectric metasurface achieved a two-order-of-magnitude enhancement in upconversion photoluminescence intensity at both 540 nm and 660 nm emission bands.
• The degree of polarization reached 0.86 at 540 nm and 0.91 at 660 nm, indicating highly polarized emission.
• Dual-band resonances were selectively excited based on the incident light's polarization state, enabling cross-polarization control.
• The metasurface's high-quality factor modes significantly enhanced the local electromagnetic field, boosting emission efficiency.
• The system demonstrated polarization-dependent switching of emission bands, enabling dynamic control of the output light.
• The results establish a pathway toward efficient, low-threshold polarization upconversion lasers using dielectric nanostructures.