Abstract: Over the past few years, the field of micro-/nano- photonics has witnessed a surge in research focused on developing innovative optical devices that offer dynamic spectra engineering. Among the materials showing promise in this area, vanadium dioxide (VO₂) can actively manipulate its refractive index via a phase transition process, enabling the dynamic manipulation of spectra. In this work, a photosensitive polymer nanocomposite with tunable effective refractive index is prepared by incorporating VO₂ nanocrystals into methacrylate monomers, which takes advantages of the phase change characteristics of VO₂ and the photopolymerization properties of the monomer. In addition, with the aid of the state-of-the-art femtosecond laser processing technology, highly precise two-dimensional and three-dimensional micro-/nano- optical structures embedded with the phase change capabilities outlined by VO₂ are achieved. Fascinatingly, the spectra measurements via Fourier transform infrared spectrometer reveal that when subjected to the critical phase transition temperatures, the printed micro-/nano- structures will undergo a thermally induced phase transition of the VO₂ nanocrystals embedded within them. Consequently, there is a discernible alteration in the effective refractive index of the optically functionalized structure, inspiring the dynamic manipulation of the short-band spectra.