  We describe here measurements with a new device, the "dichroicon," a
Winston-style light concentrator built out of dichroic reflectors, which could
allow large-scale neutrino detectors to sort photons by wavelength with small
overall light loss. Photon sorting would benefit large-scale water or ice
Cherenkov detectors such as Hyper-Kamiokande or ICECUBE by providing a measure
of dispersion, which in turn could allow improved position reconstruction and
timing. For scintillator detectors like JUNO, upgrades to SNO+ or KamLAND-ZEN,
or to water-based liquid scintillator detectors like Theia, dichroicons would
provide effective discrimination between Cherenkov and scintillation light,
allowing them to operate as true hybrid detectors.
  We include measurements with a prototype dichroicon using first a Cherenkov
source to show spectral photon sorting works as expected. We then present
measurements of two different LAB-based liquid scintillator sources, and
demonstrate discrimination between Cherenkov and scintillation light. On the
benchtop we can identify Cherenkov light with better than 90% purity while
maintaining a high collection efficiency for the scintillation light. First
results from simulations of a large-scale detector are also presented.
