High-Q photonic device for trapping and detecting a single atom on a chip

Recent progress in manufacturing high-Q dielectric microresonant structures may enable their use as photonic devices that can manipulate and/or detect single atoms on a nanometer scale. Of specific interest is the wafer-based manufacturing of resonators where good control of the physical characteristics can be achieved during fabrication and operation when integrated with other functions on the chip. We show that this "all-optical" trapping should be stable. We discuss atom detection efficiencies and the feasibility for non-destructive measurements in such systems and their dependence on key parameters such as atom distance from the surface, intensity of red- and blue-detuned laser pump fields, and disk size

Simultaneous optical trapping and detection of atoms by microdisk resonators

We propose a scheme for simultaneously trapping and detecting single atoms near the surface of a substrate using whispering gallery modes of a microdisk resonator. For efficient atom-mode coupling, the atom should be placed within approximately 150nm from the disk. We show that a combination of red and blue detuned modes can form an optical trap at such distances while the backaction of the atom on the field modes can simultaneously be used for atom detection. We investigate these trapping potentials including van-der-Waals and Casimir-Polder forces and discuss corresponding atom detection efficiencies, depending on a variety of system parameters. Finally, we analyze the feasibility of nondestructive detection

Design of microcavity resonators for single-atom detection

Whispering gallery modes of a microdisk resonator are useful for the optical detection of single rubidium and cesium atoms near the surface of a substrate. Light is coupled into two high-Q whispering-gallery modes of the disk which can provide attractive and/or repulsive potentials, respectively, via their evanescent fields. The sum potential, including van der Waals/Casimir-Polder surface forces, may be tuned to exhibit a minimum at distances on the order of 100nm from the disk surface. Simultaneously optically trapping and detecting is possible, with the back-action of an atom held in this trap on the light fields being sufficiently strong to provide a measurable effect. Atom trapping and detection depend on a variety of system parameters and experimental realizations differ for different atoms

Feasibility study of SWIR light absorption enhancement in PbS and PbSe nano-structure layers using surface plasmon polariton

We present a theoretical feasibility study of the use of reflection grating couplers in order to harness the Surface Plasmon Polariton (SPP) to increase the absorption efficiency in the short wavelength infrared (SWIR) spectral range of a novel SWIR to visible (VIS) direct up-conversion imaging device. This device detects the SWIR spectral band photons using high absorption PbSe/CdSe core-shell, PbS nano-spheres or PbSe nano-columns. In order to further enhance the absorption of the SWIR light within the nano-structure layer we propose to add another light absorption enhancement, known as SPP enhanced absorption. The idea is to cover the absorber layer surface with a structured metal layer that will ignite SPPs on the metal – dielectric interface, by coupling between the incident TM polarized photons and the SPP modes; this results in better field confinement at the interface that will further increase the SWIR absorption of this thin layer. Calculation of the field profile of the surface plasmon (SP) in the SWIR range shows perpendicular dominance of the SP’s electrical field direction on the dielectric layer side (the PbS or PbSe/CdSe absorption layer side). Based on this result, it was found that, due to the use of quantum confined and, thus, high oscillator strength nanostructures, there is only a marginal increase in the absorption and, hence, in the quantum efficiency when using the SPP enhancement technique. Nevertheless, we show that one of the proposed configurations of the metal grating coupler, having a lamellar structure with a pitch of 1.38μm, a duty cycle (DC) of 0.12μm and a height of 60nm, is predicted to increase the total layer’s absorption by 9.5%, mainly due to efficient light scattering rather than to SPP enhanced absorption

Design of a trapping potential for detecting single atoms by a microdisk resonator on a chip

We investigate simultaneous optical trapping and optical detection of a single Rb atom near the surface of a toroidal microdisk. Light is coupled into two high-Q whispering-gallery modes of the disk which provide attractive and repulsive potentials, respectively, via their evanescent fields. The sum potential including van-der-Waals and Casimir-Polder surface forces exhibits a minimum at distances of the order of 100 nm from the disk surface. The back-action of an atom held in this trap on the light fields is sufficiently strong to provide a measurable effect. We discuss atom trapping and detection properties in dependence on a variety of system parameters

The effect of volanesorsen treatment on the burden associated with familial chylomicronemia syndrome: the results of the ReFOCUS study

<p><b>Background</b>: Volanesorsen, an investigational inhibitor of apoC-III synthesis, significantly reduced triglyceride levels in clinical trials in patients with familial chylomicronemia syndrome (FCS), a rare genetic disorder characterized by marked chylomicronemia leading to a spectrum of symptoms, including recurrent abdominal pain and episodes of potentially fatal acute pancreatitis (AP).</p> <p><b>Objective</b>: To determine the effect of volanesorsen on burden of disease on patients with FCS</p> <p><b>Methods</b>: ReFOCUS was a retrospective global web-based survey open to patients with FCS who received volanesorsen for ≥3 months in an open-label extension study. The survey included questions about patients’ experiences before and after volanesorsen treatment.</p> <p><b>Results</b>: Twenty-two respondents had received volanesorsen for a median of 222 days. Volanesorsen significantly reduced the number of symptoms per patient across physical, emotional, and cognitive domains. Significant reductions from baseline were reported for steatorrhea, pancreatic pain, and constant worry about an attack of pain/AP. Respondents reported that volanesorsen improved overall management of symptoms and reduced interference of FCS with work/school responsibilities. Reductions in the negative impact of FCS on personal, social, and professional life were also reported.</p> <p><b>Conclusions</b>: Treatment with volanesorsen has the potential to reduce disease burden in patients with FCS through modulation of multiple symptom domains.</p