The study investigates the electronic properties of vanadium dioxide (VO₂) using scanning near-field infrared microscopy and far-field infrared spectroscopy. The research focuses on the insulator-to-metal transition in VO₂, which is induced by increasing temperature. The experiments reveal the presence of nano-scale metallic puddles at the onset of this transition, which exhibit divergent quasiparticle mass, a signature of the Mott transition. These findings provide insights into the electronic correlations and charge dynamics in correlated electron systems, particularly in the context of the pseudogap state and the role of lattice and electron-electron correlations in the transition. The study also discusses the implications of these results for understanding the pseudogap and "bad metal" phases in other correlated electron systems.The study investigates the electronic properties of vanadium dioxide (VO₂) using scanning near-field infrared microscopy and far-field infrared spectroscopy. The research focuses on the insulator-to-metal transition in VO₂, which is induced by increasing temperature. The experiments reveal the presence of nano-scale metallic puddles at the onset of this transition, which exhibit divergent quasiparticle mass, a signature of the Mott transition. These findings provide insights into the electronic correlations and charge dynamics in correlated electron systems, particularly in the context of the pseudogap state and the role of lattice and electron-electron correlations in the transition. The study also discusses the implications of these results for understanding the pseudogap and "bad metal" phases in other correlated electron systems.