arXiv subjects

Suvinay Goyal

Publications and source records attributed to Suvinay Goyal.

3 recordsLinked to original sources

arXiv2026

The Photonic Lantern Nuller: from concept to laboratory and on-sky demonstrations

This thesis work presents the conceptual design and experimental characterization of the Photonic Lantern Nuller instrument, which uses a multimode-to-single-mode demultiplexing waveguide to cancel out starlight while maintaining planet light, allowing for the direct characterization of planets at a telescope's diffraction limit. The PLN was experimentally characterized in the lab, where it was further enhanced using common-path wavefront sensing and control techniques, and then demonstrated on sky at the Subaru Telescope. Highlights include measured in-lab null-depths of $\sim 10^{-4}$ in three out of four ports simultaneously and on-sky null-depths of approximately $\sim 10^{-1}$ (limited by jitter and atmospheric residuals). We provide an overview of these results and discuss avenues for future work.

astro-ph.IM↗

arXiv2025

Analysis of Angular-Differential Post-Processing Algorithms for Exoplanet Direct Detection with a Photonic Lantern Nuller

Exoplanet research is essential for understanding planetary formation and the potential for life beyond our solar system. The direct imaging method captures exoplanet light while minimizing light from the host star. This is conventionally achieved with a coronagraph, which allows detailed characterization of planetary atmospheres and features. The Photonic Lantern Nuller (PLN) is an innovative instrument designed for the direct detection of closely orbiting exoplanets within the inner working angle of standard coronagraphs. Unlike traditional coronagraphs, where the planet's signal is usually rotationally invariant, with the same point-spread-function at different position angles, and which also overlaps minimally with the residual stellar signal, data from a PLN consist of a one-dimensional collection of points that do not have rotational invariance and overlap significantly with the residual starlight arising from wavefront errors. Exploiting angular diversity to subtract these stellar residuals with the PLN thus requires adapting the Angular Differential Imaging (ADI) technique for use with non-rotationally invariant planet signals at close separations, where strong self-subtraction effects occur. We reformulate ADI using principal component analysis to develop a method to extract spatial parameters of exoplanets from simulated one-dimensional PLN data. We test two variations of ADI on simulated data and show that injecting an antiplanet signal before stellar estimation helps localize the planet due to self-subtraction at lower separations.

astro-ph.IM↗

arXiv2025

Implicit Electric Field Conjugation with the Photonic Lantern Nuller

The Photonic Lantern Nuller (PLN) is an instrument concept designed to characterize exoplanets within a single beam-width from its host star. The PLN leverages the spatial symmetry of a mode-selective photonic lantern (MSPL) to create nulled ports, which cancel out on-axis starlight but allow off-axis exoplanet light to couple. The null-depths are limited by wavefront aberrations in the system as well as by imperfections in the lantern. We show that the implicit electric field conjugation algorithm can be used to reduce the stellar coupling through the PLN by orders of magnitude while maintaining the majority of the off-axis light, leading to deeper null depths (~10^{-4}) and thus higher sensitivity to potential planet signals. We discuss a theory for the tradeoff we observed between the different ports, where iEFC improves the nulls of some ports at the expense of others, and show that targeting one port alone can lead to deeper starlight rejection through that port than when targeting all ports at once. We also observe different levels of stability depending on the port and discuss the implications for practically implementing this technique for science observations.

astro-ph.IM↗