Description
The detection and characterisation of exoplanets requires the suppression of the overwhelming glare of their host stars while preserving the much fainter planetary signal. We present GLINT (Guided-Light Interferometric Nulling Technology), which is a nuller interferometer operating within the SCExAO instrument at the Subaru Telescope. This presentation introduces the current GLINT architecture, based on a three-input integrated photonic beam combiners that coherently combine multiple Subaru sub-apertures. The photonic design provides precise optical path matching, passive stability, and simultaneous photometric and interferometric outputs, enabling accurate calibration of the interferometric signals. Complimenting the photonic device, we present the successful implementation of real-time fringe tracking, which maintains the destructive interference condition during on-sky observations. We also outline the planned implementation of amplitude tracking to actively balance the flux between interferometric arms, further improving null stability and calibration accuracy.
Finally, we present recent engineering observations demonstrating the instrument's on-sky performance. Measurements of the resolved star Alf Boo validate the stability of the fringe-tracking system and quantify the achievable null performance under realistic observing conditions. Observations of a binary star further demonstrate GLINT's ability to recover astrophysical interferometric signals while operating in nulling mode, highlighting its capability as both an engineering testbed and a pathfinder scientific instrument.
These results represent an important milestone towards future photonic nulling interferometers, demonstrating that integrated beam combiners, real-time fringe control, and amplitude stabilisation provide a promising path toward the direct detection and spectroscopic characterisation of nearby exoplanets.
| I am the presenting author | Yes |
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