<p>Niobium pentoxide (Nb₂O₅) is a semiconductor material that has recently been well focused in literature and research due to its remarkable properties. This study suggests preparing a new Au@Nb₂O₅ core@shell nanocomposite using pulsed laser ablation in liquid (PLAL) with a pure Nb target in an Au colloidal solution. The technique exploits the disadvantages of commonly used approaches for nanocomposites with unique properties and it has been extensively maintained a characterization process for the prepared Au@Nb₂O₅ to study the nanoparticles’ optical and morphological properties as a function of various laser fluences and used for optoelectronic applications. X-ray diffraction patterns confirm the formation of a polycrystalline structure. Orthorhombic T-Nb₂O₅ and monoclinic H- Nb₂O₅ structures were confirmed in the Au@Nb₂O₅ NPs at (2θ = 25.7° and 58.8°). FE-SEM and TEM imaging illustrated the formation of the core–shell structure of Au@Nb₂O₅ nanocomposites. Also, TEM revealed morphological alteration of the shell thickness corresponding to the size variation of Au@Nb₂O₅ nanoparticles. Average shell thickness increased from 7.1 to 22.3 nm with increased laser fluence. UV–VIS study indicates the modification of band gap energy and visual absorption with the contrast of the particles in the Nb₂O₅ nanoparticles (NPs) resulting from changing the laser fluence (was reduced from 2.54 to 2.43eV). AFM results revealed an increase in average particle size from 48 to 251 nm. According to the same measurement, the RMS roughness increased with increasing laser fluence. According to the experimental results, the photodetector that was constructed with the ideal laser fluence showed a photosensitivity of 0.0116 A/W at 375 nm.</p>