2022/06/10 by Nick Cvetojević, Cvetojevic, Nick, Frantz Martinache +15
Biochemistry, Genetics and Molecular Biology · Computer Science · Physics and Astronomy · #Adaptive optics and wavefront sensing #Advanced Fluorescence Microscopy Techniques #FOS: Physical sciences #Instrumentation and Methods for Astrophysics (astro-ph.IM) #Optical measurement and interference techniques
paper · doi:10.48550/arxiv.2206.04977
openalex publication_date 2022/06/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The use of interferometric nulling for the direct characterization of extrasolar planets is an exciting prospect, but one that faces many practical challenges when deployed on telescopes. The largest limitation is the extreme sensitivity of nullers to any residual optical path differences between the incoming telescope beams even after adaptive optics or fringe-tracker correction. The recently proposed kernel-nulling architecture attempts to alleviate this by producing the destructive interference required for nulling, in a scheme whereby self-calibrated observables can be created efficiently, in effect canceling out residual atmospheric piston terms. Here we experimentally demonstrate for the first time a successful creation of self-calibrated kernel-null observables for nulling interferometry in the laboratory. We achieved this through the use of a purpose-built photonic integrated device, containing a multimode interference coupler that creates one bright, and two nulled outputs when injected with three co-phased telescope beams. The device produces the nulled outputs in a way that, by the subtraction of the measured output flux, create a single self-calibrated kernel-null. We experimentally demonstrate the extraction of kernel-nulls for up to 200 nm induced piston error using a laboratory test-bench at a wavelength of 1.55 μm. Further, we empirically demonstrate the kernel-null behaviour when injected with a binary companion analogue equivalent to a 2.32 mas separation at a contrast of 10-2, under 100 nm RMS upstream piston residuals.