  The development of wide-area cryogenic light detectors with baseline energy
resolution lower than 20 eV RMS is essential for next generation bolometric
experiments searching for rare interactions. Indeed the simultaneous readout of
the light and heat signals will enable background suppression through particle
identification. Because of their excellent intrinsic energy resolution, as well
as their well-established reproducibility, Kinetic Inductance Detectors (KIDs)
are good candidates for the development of next generation light detectors. The
CALDER project is investigating the potential of phonon-mediated KIDs. The
first phase of the project allowed to reach a baseline resolution of 80 eV
using a single KID made of aluminium on a 2x2 cm\tmrsup{$2$} silicon substrate
acting as photon absorber. In this paper we present a new prototype detector
implementing a trilayer aluminium-titanium-aluminium KID. Taking advantage of
the superconducting proximity effect the baseline resolution improves down to
26 eV.
