NOTT laboratory nulling: first dispersed ambient measurements

The KU Leuven group has published a laboratory status paper on Asgard/NOTT, the L-band nulling instrument we are building for the VLTI. Led by T. Mattheussen, the work reports the first spectrally dispersed null measurements on the four-beam test bench in ambient conditions, with a revised acquisition and calibration pipeline and a first look at the splitting ratios of the Gallium Lanthanum Sulfide photonic chip.

Those dispersed measurements complement earlier broadband cryogenic chip tests. The paper is a progress report: the present ambient contrast is still well short of the on-sky goal, and it lays out the next bench changes — including intensity matching to the chip’s couplers — before the final cryostat and camera are used to repeat the assessment. The cryogenic spectrograph and Hawaii-2RG detector were being integrated in Leuven in July 2026.

I am a co-author and PI of the ERC-funded SCIFY project that is building NOTT.

Read Asgard/NOTT: Status of laboratory nulling performance (SPIE 14148, July 2026).