Cryogenic characterization of the grating vector APP coronagraph for the upcoming ERIS instrument at the VLT
We present results from a cryogenic characterization of the grating vector Apodizing Phase Plate (gvAPP) coro- nagraph that will be used in the upcoming instrument ERIS (Enhanced Resolution Imager and Spectrograph) at the VLT. ERIS consists of a 1-5 μm imager (NIX) and a 1 2.5 μm integral field spectrograph (SPIFFIER), both fed by the Adaptive Optics Facility of UT4 to yield diffraction-limited spatial resolution. A gvAPP coronagraph will be included in the NIX imager to enable high-contrast imaging observations, which will be particularly powerful for the direct imaging of exoplanets at L and M bands ( 3-5 μm) and will compliment the current capabilities of VLT/SPHERE and surpass the capabilities of VLT/NACO. We utilize the near-infrared test bench of the Star and Planet Formation group at ETH Zurich to measure key properties of the gvAPP coronagraph at its operating wavelengths and under the vacuum/cryogenic ( 70 K) conditions of the future ERIS instrument.