17 research outputs found
Blood, Milk, and My Trusty Old Easel: Re-examining Issues of Salvation in Medieval (and Modern) Altarpieces
Magnetic Exciton-Polariton with Strongly Coupled Atomic and Photonic Anisotropies
Anisotropy plays a key role in science and engineering. However, the
interplay between the material and engineered photonic anisotropies has hardly
been explored due to the vastly different length scales. Here we demonstrate a
matter-light hybrid system, exciton-polaritons in a 2D antiferromagnet, CrSBr,
coupled with an anisotropic photonic crystal (PC) cavity, where the spin,
atomic lattice, and photonic lattices anisotropies are strongly correlated,
giving rise to unusual properties of the hybrid system and new possibilities of
tuning. We show exceptionally strong coupling between engineered anisotropic
optical modes and anisotropic excitons in CrSBr, which is stable against
excitation densities a few orders of magnitude higher than polaritons in
isotropic materials. Moreover, the polaritons feature a highly anisotropic
polarization tunable by tens of degrees by controlling the matter-light
coupling via, for instance, spatial alignment between the material and photonic
lattices, magnetic field, temperature, cavity detuning and cavity
quality-factors. The demonstrated system provides a prototype where atomic- and
photonic-scale orders strongly couple, opening opportunities of photonic
engineering of quantum materials and novel photonic devices, such as compact,
on-chip polarized light source and polariton laser
2D Semiconductor Nonlinear Plasmonic Modulators
A plasmonic modulator is a device that controls the amplitude or phase of
propagating plasmons. In a pure plasmonic modulator, the presence or absence of
a pump plasmonic wave controls the amplitude of a probe plasmonic wave through
a channel. This control has to be mediated by an interaction between disparate
plasmonic waves, typically requiring the integration of a nonlinear material.
In this work, we demonstrate the first 2D semiconductor nonlinear plasmonic
modulator based on a WSe2 monolayer integrated on top of a lithographically
defined metallic waveguide. We utilize the strong coupling between the surface
plasmon polaritons, SPPs, and excitons in the WSe2 to give a 73 percent change
in transmission through the device. We demonstrate control of the propagating
SPPs using both optical and SPP pumps, realizing the first demonstration of a
2D semiconductor nonlinear plasmonic modulator, with a modulation depth of 4.1
percent, and an ultralow switching energy estimated to be 40 aJ
Problems in the assessment of magnesium depletion in the rat by in vivo 31P NMR
Prior in vitro studies, utilizing 31Pn uclear magnetic resonance (31PN MR) to measure the chemical shift (CT) of 0-ATP and lengthening of the phosphocreatine spin-spin (7"') relaxation time, suggested an assessment of their efficacy in measuring magnesium depletion in vivo. Dietary magnesium depletion (Me rats there was a significant change in brain j3-ATP shift (16.15 vs 16.03 ppm, P < 0.05). These chemical shifts gave a calculated free [Mg"] of 0.71 mM (control) and 0.48 mM (MgZ+ 15.99 ppm, controls 15.96 ppm), corresponding to a calculated free M P of 0.83 and 0.95 mM, respectively. Phosphccreatine Tz (Carr-Purcell, spin-echo pulse sequence) was no different with M e + 92 ms). 3'P NMR is severely limited in its ability to detect dietary magnesium depletion in vivo. Measurement of j3-ATP shift in brain may allow studies of the effects of interaction in group studies but does not allow prediction of an individual magnesium status
Macroscopic transition metal dichalcogenides monolayers with uniformly high optical quality
The optical quality of large-area transition metal dichalcogenide (TMD) monolayers is usually limited by surface defects and inhomogeneities. Here, the authors report a method based on 1-dodecanol encapsulation to improve the optical properties of TMD monolayers over mm-scale, enabling the fabrication of an array of polariton photonic crystal cavities
Toward the accurate modeling of amorphous nonlinear materialspolymer stress relaxation (I)
We expand our analytical modeling strategy for polymer non-linear stress relaxation (A) to specify the remaining steps to accurately deal with the nonaffine nature of the materials' local strains and stresses relative to their average overall values, and (B) to make it consistent with a new cooperative theory of amorphous materials dynamics, providing a model of tunable fragility that sheds light to most aspects of the behavior, including the glass transition. The stress relaxation models (1) describe a nonlinear (strain-dependent) behavior that becomes linear at very low strains, (2) quantify the effect of temperature, (3) may quantify the effects of changes in free volume, and (4) ensure very fast computations of the materials' response irrespective of the experimental time scale. The models are sensitive to the influence of different initial states of the material, as may result from varying degrees of molecular orientation and aging levels, and are able to predict from experimental stress relaxation moduli (for a poly (methylmethacrylate)PMMA and a bis-phenol-A polycarbonatePC) the values of the crossover frequency, (c), crossover temperature, T-c, and the minimum activation energy, in addition to the initial and long-time plateau moduli, in agreement with independently measured values. POLYM. ENG. SCI., 56:348-360, 2016. (c) 2016 Society of Plastics Engineer