Junho Lee

Femtosecond X-ray Tracking of Oxygen Vacancy-Driven Shallow-to-Deep Trap Transition and Its Impact on Charge Carrier Dynamics in Blue TiO2

Abstract Oxygen vacancies introduced by self-reduction are central to the enhanced light absorption and photocatalytic activity of blue TiO2, yet how they reshape the ultrafast dynamics of photogenerated charge carriers has remained unresolved. Here, we directly track these dynam...

Dispersion-Contrasting Dual-Layer Metalens for Hybrid Chromatic-Aberration Correction in the Visible

Abstract Metalenses offer a pathway toward flat, wafer-level optics, but their translation to mobile imaging has been hindered by the difficulty of achieving broadband performance at millimeter-scale apertures. Here we report a visible metalens that imparts a wavelength-invariant...