Many body solid-state systems have attracted increasing interest due to their diverse quantum phases and novel physical properties. Such unusual properties allow people to overcome the limitations caused by materials in many nanophotonics applications such as sensing, imaging, virtual reality, optical computing, etc. To date, many new material platforms have been proposed, improving the performance of nanophotonics devices. In this dissertation, I will demonstrate the limitation of the development of nanophotonics, and show the possible revolution raised from a two-dimensional strongly correlated material, 1T-TaS2, one of the many-body solid-state systems which exhibit quantum charge-density-wave (CDW) phases over a large temperature range. First, I will discuss the physics understanding of strongly correlated materials and charge density wave quantum phase. Next, I will present the optical characterization of 1T-TaS2 in its CDW phases under external stimuli, including light, temperature, and in-plane bias. This material exhibits a unitary order change of refractive index under white light illumination, and MHz switching speed at room temperature. Furthermore, I will propose a physics model to understand the mechanism of such tunability. Nevertheless, the tunable optical properties of 1T-TaS2 can be implemented in tunable nanophotonics applications. I will show the theoretical demonstration of some tunable nanophotonic devices by using the 1T-TaS2, and the experimental results of the tunable meta-grating and meta-color-filter. Additionally, I will present the theoretical realization of the correlation behavior of percolation systems by using the renormalization theory.