Fine-grained calorimeters for experiments at CLIC and FCC-ee

We present optimisation studies for detectors being designed for future $e^+e^−$ colliders such as CLIC and FCC-ee, using particle-flow calorimetry. Surrounding a large silicon tracker volume, a very fine-grained ECAL is envisaged, with 40 Si-W layers and a lateral segmentation of $5\times5~$mm$^2$. Beyond the ECAL, a steel-scintillator HCAL is placed, with 60 (44) active layers for CLIC (FCC-ee) consisting of $30\times30~$mm$^2$ scintillator tiles coupled to SiPMs. The newly developed software chain based on the DD4Hep detector description toolkit is used for the studies, together with the PANDORA particle flow algorithms. Results obtained for the jet energy resolution as well as particle identification efficiencies for the two detector models designed for CLIC and FCC-ee are presented in this contribution.