Fig. 4
From: Stacking angle-tunable photoluminescence from interlayer exciton states in twisted bilayer graphene
TA spectrum estimates of exciton binding energy. a Two measures methods of Eb, blue arrows: pump XS, with probe ESA to intraband exciton band-edge states near the e-h continuum. gray arrows: 2-photon pump, probe at XS. (right inset) Equivalent experiments in a vHs model. b Blue and gray TA spectra independently estimate Eb at ~0.7 eV for θ = 7.9°. tBLG absorption spectra is in green. c Interlayer relaxation kintetics for both intraband and interband probe are delayed relative to the faster thermalization rate of 0° bilayer graphene shown in gray
