Crystal field optimization and fluorescence enhancement of a Mn-doped fluoride red phosphor with excellent stability induced by double-site metal ion replacement for warm WLED.

The effective double-site metal ion replacement strategy was adopted to optimize the crystal field environment of a Mn-activated fluoride phosphor. In this study, a series of KBaSiGeF:Mn phosphors with optimized fluorescence intensity, excellent water resistance, and outstanding thermal stability was synthesized. The composition adjustment includes two different types of ion substitution based on the BaSiF:Mn red phosphor: [Ge → Si] and [K → Ba].

Enhanced Readout from Spatial Interference Fringes in a Point-Source Cold Atom Inertial Sensor.

When the initial size of an atom cloud in a cold atom interferometer is negligible compared to its size after free expansion, the interferometer is approximated to a point-source interferometer and is sensitive to rotational movements by introducing an additional phase shear in the interference sequence. This sensitivity on rotation enables a vertical atom-fountain interferometer to measure angular velocity in addition to gravitational acceleration, which it is conventionally used to measure. The accuracy and precision of the angular velocity measurement depends on proper extraction of frequency and phase from spatial interference patterns detected via the imaging of the atom cloud, which is usually affected by various systematic biases and noise.

Spatial filtering of Zeeman sub-states in an atomic fountain.

In an atomic fountain, atoms in motion can be spatially separated into discrete Zeeman sub-states by magnetically induced Stern-Gerlach effect. With resonant light pulses acting as a shutter, specific states are selected for subsequent experiments. Such separation-selection process in atomic optics is the analogue of a spatial filter in physical optics which selects and purifies the modes of light.