Novel implementation of a Kalman filter for speckle nulling with a fiber injection unit

Abstract

High dispersion coronagraphy (HDC) is a technique that combines high contrast imaging techniques with high spectral resolution spectroscopy to directly characterize exoplanets and provide key information such as chemical composition, temperature, and rotational velocity. A consequence of adaptive optics systems used in direct imaging is the formation of residual bright spots of star lights, called speckles, in the final image. Due to the large difference in brightness between host stars and their planets, these speckles can easily obscure potential exoplanets. In a previous demonstration, it was shown that using monochromatic light and a fiber injection unit (FIU), simulated exoplanet light can be directed to a high-resolution spectrograph. The method had speckle suppression that exceeding conventional image-based speckle nulling. With a previous Kalman filter estimator implementation, we found that with the implementation of the algorithm, speckle suppression was even more stable and outperformed traditional speckle nulling. In this update to the estimator, progress has been made in terms of a new filter design, and better estimates of the physical parameters in the laboratory, resulting in a higher speckle nulling performance.