Fig. 5: Outgoing versus incoming resonant conditions.

a Low-temperature (T = 5 K) PL spectrum of the WSe₂ ML encapsulated in hBN flakes measured using excitation energy of 2.4 eV and power of 150 μW. The lines' assignments are as follows: X—neutral exciton; XX—neutral biexciton; T^S and T^T—singlet (intravalley) and triplet (intervalley) negatively charged excitons, respectively; X^I and X^D—momentum- and spin-forbidden neutral dark excitons, respectively; XX⁻—negatively charged biexciton; T^D—negatively charged dark exciton (dark trion); X\({}_{{{{{\rm{E}}}}}^{{\prime\prime} }({{\Gamma }})}^{{{{\rm{D}}}}}\)—phonon replica of the X^D complex. b, c False-colour maps of low-temperature (T = 5 K) optical response of the WSe₂ MLs encapsulated in hBN under excitation of tuneable-energy lasers (excitation power ~ 10 μW) measured in the vicinity of the outgoing and incoming resonance conditions of Raman scattering with the X line, respectively. The colour scales in panels (b) and (c) have been normalised to the maximum intensity. The vertical red dashed lines denote the edge of the used long-pass filters.