Related papers: New method to achieve the proper polarization stat…
High-energy vortex $\gamma$ photons have significant applications in many fields, however, their generation and angular momentum manipulation are still great challenges. Here, we first investigated the generation of vortex $\gamma$ photons…
The exploration of circumstellar environments by means of direct imaging to search for Earth-like exoplanets is one of the challenges of modern astronomy. One of the current limitations are evolving non-common path aberrations (NCPA) that…
Detection and characterization of exoplanets by direct imaging requires a coronagraph designed to deliver high contrast at small angular separation. To achieve this, an accurate control of low order aberrations, such as pointing and focus…
The High Contrast spectroscopy testbed for Segmented Telescopes (HCST) is being developed at Caltech. It aims at addressing the technology gap for future exoplanet imagers and providing the U.S. community with an academic facility to test…
Direct imaging of exoplanets by reflected starlight is extremely challenging due to the large luminosity ratio to the primary star. Wave-front control is a critical technique to attenuate the speckle noise in order to achieve an extremely…
By using an ensemble of nitrogen-vacancy (NV) centers, the vector components of a time-varying (AC) magnetic field are measured in a phase sensitive manner. This allows for the determination of the magnetic field's polarization. This…
Valley-contrast physics has gained considerable attention, particularly for realizing photonic topological insulators (PTIs) that support reflection-free valley-polarized edge modes (VPEMs) in the absence of inter-valley scattering. It is…
We propose a stereographical-visualization scheme for a polarization state by two-dimensional imaging of a weak value with a single setup. The key idea is to employ Laguerre-Gaussian modes or an optical vortex beam for a probe state in weak…
Uncorrected wavefront errors create speckle noise in high-contrast observations at small inner-working angles. These speckles can be sensed and controlled by using coronagraph integrated wavefront sensors. Here, we will present how the…
Coronal oscillations offer insight into energy transport and driving in the solar atmosphere. Knowing its polarisation state helps constrain a wave's displacement and velocity amplitude, improving estimates of wave energy flux and…
Well over 700 exoplanets have been detected to date. Only a handful of these have been observed directly. Direct observation is extremely challenging due to the small separation and very large contrast involved. Imaging polarimetry offers a…
Vortices are widely studied in fields ranging from nonlinear optics to magnetic systems and superconductors. A vortex carries a binary information corresponding to its topological charge, `plus' or `minus', that can be used for information…
We report on the performance of a vector apodizing phase plate coronagraph that operates over a wavelength range of $2-5 \mu$m and is installed in MagAO/Clio2 at the 6.5 m Magellan Clay telescope at Las Campanas Observatory, Chile. The…
Polarized light microscopy provides high contrast to birefringent specimen and is widely used as a diagnostic tool in pathology. However, polarization microscopy systems typically operate by analyzing images collected from two or more light…
With a clear circular aperture, the vortex coronagraph perfectly cancels an on-axis point source and offers a 0.9 or 1.75 lambda/D inner working angle for topological charge 2 or 4, respectively. Current and near-future large telescopes are…
A Highly flexible and efficient method of generating stable radially and Azimuthally polarized perfect optical vortex beams and all higher-order cylindrical vector vortex beams are proposed and demonstrated. The method is the most…
Since the start of operations in 2011, the VLT Survey Telescope (VST) has been one of the most efficient wide-field imagers in the optical bands. However, in the next years the Vera C. Rubin Observatory Legacy Survey of Space and Time…
Stellar coronagraphs designed for high-contrast imaging of exoplanets inevitably introduce a small amount of instrumental polarization, called \emph{secondary polarization}. At the contrast levels required to detect and characterize…
Polarimetric imaging is one of the most effective techniques for high-contrast imaging and characterization of circumstellar environments. These environments can be characterized through direct-imaging polarimetry at near-infrared…
A multitude of coronagraphic techniques for the space-based direct detection and characterization of exo-solar terrestrial planets are actively being pursued by the astronomical community. Typical coronagraphs have internal shaped focal…