Advancement in narrow-band filters at LBC-like instruments for multiple stars populations

The narrow-band filters based on thin layers of dielectric material present a blue shift of the transmission curve with a larger angle from the normal. Fast and large field of view instruments limit the ability of such filters to select small spectral features that can highlight multiple star populations in globular clusters. We will to make an instrument like the first focus one of the LBT the spearhead facility to identify the multiple populations in galactic globular clusters. A new set of simulations has been developed to identify the best thin-layer filter to be used to separate populations with different light element abundances. We also built an optomechanical set-up to test the filter behavior in a LBC-like configuration. We present here the simulation strategy and some transmission curve obtained with the laboratory set-up.