A5107951691- Adaptive optics and wavefront sensing
- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Optical Polarization and Ellipsometry
- CCD and CMOS Imaging Sensors
- Calibration and Measurement Techniques
- Optical measurement and interference techniques
- Spacecraft and Cryogenic Technologies
- Photoacoustic and Ultrasonic Imaging
- Advanced X-ray Imaging Techniques
- Superconducting and THz Device Technology
- Optical Coatings and Gratings
- Plant and animal studies
- Infrared Target Detection Methodologies
- Astrophysics and Star Formation Studies
- Planetary Science and Exploration
- Cocoa and Sweet Potato Agronomy
- Interactive and Immersive Displays
University of California, Santa Barbara
2023-2025
California Institute of Technology
2017-2019
Space Telescope Science Institute
2019
Direct exo-Earth imaging is a key science goal for astronomy in the next decade. This ambitious task imposes target contrast of ~10^-7 at wavelengths from I to J-band. In our prior study, we determined that polarization aberrations can limit achievable 10^-5 10^-6 infrared. However, these results assumed perfect coronagraph coupled telescope with an ideal coating on each mirrors. this study seek understand influence segment-to-segment variations coronagraphy and polarimetry. We use Poke...
Direct exo-earth imaging is a key science goal for astronomy in the next decade. This ambitious task imposes target contrast of ≈ 10^ at wavelengths from I to J-band. In our prior study, we determined that polarization aberrations can limit achievable 10^-5 10^-6 infrared. However, these results assumed perfect coronagraph coupled telescope with an ideal coating on each mirrors. this study seek understand influence segment-to-segment variations coronagraphy and polarimetry. We use Poke...
A major science goal of future, large-aperture, optical space telescopes is to directly image and spectroscopically analyze reflected light from potentially habitable exoplanets. To accomplish this, the system must suppress diffracted star reveal point sources approximately ten orders magnitude fainter than host at small angular separation. Coronagraphs with microdot apodizers achieve theoretical performance needed Earth-like planets a range possible telescope designs, including those...
The High Contrast Spectroscopy Testbed for Segmented Telescopes (HCST) at Caltech is aimed filling gaps in technology future exoplanet imagers and providing the U.S. community with an academic facility to test components techniques high contrast imaging segmented ground-based telescope (TMT, E-ELT) space-based telescopes (HabEx, LUVOIR). HCST will be able simulate geometries up 1021 hexagonal segments time-varying external wavefront disturbances. It also contains a corrector module based on...
Imaging Earth-like exoplanets with future space telescopes will require a coronagraph instrument that is capable of creating dark zone in the starlight at image plane ten orders magnitude fainter than off-axis host star. What more, must simultaneously provide stable and high throughput over angular separations correspond to habitable zones around nearby Sun-like stars (~10-100 milliarcseconds). Since pupils most large-aperture telescope architectures are likely be obstructed by secondary...
The Visible Aperture Masking Polarimetric Imager for Resolved Exoplanetary Structures (VAMPIRES) is a visible light instrument on the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system. In previous work, instrumental polarization (IP) and crosstalk of VAMPIRES was characterized from measurements with polarized internal calibration source. this we use unpolarized standard star observations to estimate Subaru's Nasmyth mirror (M3) quantify overall system Mueller matrix model's...
We present significant upgrades to the VAMPIRES instrument, a visible-light (600 nm 800 nm) high-contrast imaging polarimeter integrated within SCExAO on Subaru telescope. Key enhancements include new qCMOS detectors, coronagraphs, polarization optics, and multiband mode, improving sensitivity, resolution, efficiency. These position as powerful tool for studying sub-stellar companions, accreting protoplanets, circumstellar disks, stellar jets, mass-loss shells, solar system objects. The...
Whilst many algorithms exist for interferometric image reconstruction, there are not yet polarimetric reconstruction. The polarisation state of light contains critical information otherwise uncaptured by standard, unpolarised interferometry, and major facilities now looking towards fully leveraging this to broaden the observational reach new existing instruments. Polarimetric reconstruction has additional challenges compared as reconstructions polarised images (Stokes I, Q U) spatial maps...
Abstract We present significant upgrades to the Visible Aperture-Masking Polarimetric Imager/Interferometer for Resolving Exoplanetary Signatures (VAMPIRES) instrument, a visible-light (600–800 nm) high-contrast imaging polarimeter integrated within SCExAO on Subaru telescope. Key enhancements include new qCMOS detectors, coronagraphs, polarization optics, and multiband mode, improving sensitivity, resolution, efficiency. These position VAMPIRES as powerful tool studying sub-stellar...
The differential polarization visibilities RQ and RU of an object are the ratios its corresponding to orthogonal polarizations, interferometric analogs Stokes Q U intensity images. measurement visibilitites can be used for constraining inner parts circumstellar envelopes young or evolved stars at diffraction limited resolution feeding telescope. We demonstrate estimation both amplitude phase from data obtained using SCExAO VAMPIRES through full pupil 8-m Subaru telescope speckle polarimetry...
The Visible Aperture Masking Polarimetric Imager for Resolved Exoplanetary Structures (VAMPIRES) is a visible light instrument on the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system. To characterize Instrumental Polarization (IP) and crosstalk of system, measurements with polarized internal calibration source were taken to provide diattenuation retardance estimates components downstream telescope mirrors. Using Markov Chain Monte Carlo (MCMC) simulations, we developed Mueller...
We discuss the use of parametric phase-diverse phase retrieval to characterize and optimize transmitted wavefront a high-contrast apodized pupil coronagraph with without an apodizer. apply our method correct HiCAT (High contrast imager for Complex Aperture Telescopes) coronagraphic testbed. This correction requires series calibration steps, which we describe. The improves system from 16 nm RMS 3.0 case where uniform circular aperture is in place. further measure apodizer place be 11.7 RMS....
High dispersion coronagraphy (HDC) is a technique that combines high contrast imaging techniques with spectral resolution spectroscopy to directly characterize exoplanets and provide key information such as chemical composition, temperature, rotational velocity. A consequence of adaptive optics systems used in direct the formation residual bright spots star lights, called speckles, final image. Due large difference brightness between host stars their planets, these speckles can easily...