Optimizing the spontaneous-emission of far-UVC phosphors

Abstract

Far-UVC light can enable virus-deactivation while remaining harmless to human tissues. This triggered great efforts to create far-UVC light sources with sufficient emission power and efficiency. However, current sources, such as mercury lamps, KrCl excimer lamps, and LEDs, are made from hazardous chemicals or are limited by low efficiency. Consequently, an alternative approach for reaching the far-UVC is now receiving renewed interest: using phosphors for converting higher frequencies to the desired range of far-UVC. However, this concept is limited by the phosphor's conversion efficiency. In this paper, we propose to utilize principles of nanophotonics to create far-UVC sources. Specifically, we design a phosphor-dielectric multilayer that increases the efficiency of far-UVC light conversion and controls the intrinsic emission properties, including the angular spectrum and emission rate, by shaping the local density of photonic states. To exemplify our approach, we design an aperiodic multilayer nanostructure made of the phosphor material YPO4:Pr3+, showing an increase in light extraction by a factor of 3 compared to naïve bulk structures. Our approach can be applied to any phosphor material and any emitter geometry, opening avenues for engineering nanophotonic light sources in the far-UVC and other spectral regimes.

Enhanced Imaging Using Inverse Design of Nanophotonic Scintillators

“…[ 56,57 ] A key advantage of aperiodic structures is their extremely large parameter space to optimize over, which became feasible in recent years thanks to advances in optimization techniques and the ability to describe such structure with a partially analytical formalism. [ 45 ]…”

“…[56,57] A key advantage of aperiodic structures is their extremely large parameter space to optimize over, which became feasible in recent years thanks to advances in optimization techniques and the ability to describe such structure with a partially analytical formalism. [45] Our methodology can be used for arbitrary emitters, optimized separately for any emission spectrum, material combination, size, and type of incoming energetic particle. Moreover, other optimization algorithms can be used depending on the application's figure of merit and the constraints.…”

“…To solve the optimization problem we leverage existing optimization algorithms such as the interior-point method. [44,45] As an example, phosphors are used in many applications as converters of light wavelength. In such applications, the phosphor absorbs light of a particular wavelength and then emits light at a longer wavelength.…”

“…To solve the optimization problem we leverage existing optimization algorithms such as the interior‐point method. [ 44,45 ]…”

Large-Area Photonic Bound State in the Continuum for Ultraviolet and Deep-Blue Emission for Organic, Inorganic, and Perovskite Scintillators

“…It is beneficial for boosting the light matter interactions, which can result in brighter and faster emission of light [11]. Among numerous demonstrated applications, recently there have been attempts to employ Purcell effect in scintillating media [12]- [14] or in UV-C light sources [15]. In particular for the first, there is hitherto no observation of the shortening of the nanosecond range scintillation decay times [16] that can change many scintillator applications in timing, e.g.…”