The Very Large Telescope Interferometer (VLTI) is currently the best infrastructure
for long-baseline interferometry in particular in terms of sensitivity and accessibility
to the general user. MATISSE, installed at the VLTI focus since end of 2017, belongs
to the second generation instruments. MATISSE, the Multi AperTure mid-Infrared SpectroScopic
Experiment, for the first time accesses high resolution imaging over a wide spectral
domain of the mid-infrared. The instrument is a spectro-interferometric imager in
the atmospheric transmission windows called L, M, and N, from 2.8 to 13.0 microns,
and combines four optical beams from the VLTI's unit or auxiliary telescopes. The
instrument utilises a multi-axial beam combination that delivers spectrally dispersed
fringes. The signal provides the following quantities at several spectral resolutions:
photometric flux, coherent flux, visibility, closure phase, wavelength differential
visibility and phase, and aperture-synthesis imaging. MATISSE can operate as a stand
alone instrument or with the GRA4MAT set-up employing the GRAVITY fringe tracking
capabilities. The updated MATISSE performance are presented at the conference together
with a selection of two front-line science topics explored since the start of the
science operations in 2019. Finally we present the perspective and benefit of two
technical improvements foreseen in the coming years: the MATISSE-Wide off-axis fringe
tracking capability and new adaptive optics for the UTs in the context of the GRAVITY+
project.
