HCIL
Full testbed name
High Contrast Imaging Laboratory (HCIL)
Managing institution
Princeton University
Person to contact
People willing to give talks
N. Jeremy Kasdin
He Sun
Christian Delacroix
Main scientific focus
HCIL is designed to demonstrate cutting-edge technologies for exoplanet direct imaging and characterization from space-based platforms. The laboratory simulates an integrated telescope and coronagraph instrument, operating in the visible to near-infrared, similar to that baselined for the WFIRST mission. Our specific focus is the development and validation of the shaped pupil coronagraph along with various model-based wavefront control and estimation techniques. On-going developments of the HCIL include the addition of low-order wavefront sensing (LOWFS) and an integral field spectrograph (IFS).
Environment of the testbed
The testbed is located in a 900 sq. ft. clean room with temperature and humidity control. The testbed is equipped with vibration isolation and a clean air system designed for optical research.
Optical design map
Current configuration
Future configuration
Key hardware items
- A star-planet simulator using two fiber sources with different wavelengths is used as the source. An off-axis parabola (OAP) is used to create the collimated beam.
- Two Boston MicroMachine kilo-DMs with 952 active actuators on each are used for wavefront control and estimation.
- The starlight diffraction pattern is modified by a rippled-shaped pupil coronagraph (SPC) and the energy outside of the dark holes is blocked using a bowtie-shaped focal plane mask (FPM).
- A science camera (QSI model RS 6.1s) is placed on a 300mm motorized stage for focal plane imaging and phase retrieval.
Current status
Using the shaped pupil coronagraph only, the testbed can reach a contrast of 1x10^(-4). The addition of the 2 -DM focal plane wavefront control improves the contrast to 1x10^(-7). Several new wavefront control and estimation algorithms, including EFC, stroke minimization, Kalman filtering, and extended Kalman filtering, have been demonstrated in this layout. Current research is directed at achieving end-to-end system identification and reinforcement learning control.
Future Developments: The testbed will be equipped with low-order wavefront sensing based on the reflected light from the FPM in the near future. A lenslet-based integral field spectrograph (IFS) is under development as a demonstration for the WFIRST coronagraph instrument (CGI). It features an 18% band around 660nm with a spectral resolution of 50 and will be used to demonstrate IFS-based closed-loop broadband wavefront control.
Software language
Matlab, some Python
Is this software shared?
Currently private, our plan is to translate our Matlab codes into an open source Python package.
Reference papers
The shaped pupil coronagraph for planet finding coronagraphy: optimization, sensitivity, and laboratory testing, Kasdin et al. 2004
Optimal dark hole generation via two deformable mirrors with stroke minimization, Pueyo et al. 2009
Kalman filtering techniques for focal plane electric field estimation, Groff and Kasdin 2013
Recursive starlight and bias estimation for high-contrast imaging with an extended Kalman filter, Riggs, Kasdin, and Groff 2016
Methods and limitations of focal plane sensing, estimation, and control in high-contrast imaging, Groff et al. 2015
Identification of the focal plane wavefront control system using EM algorithm, Sun, Kasdin, and Vanderbei 2017