<p>The current study discusses the role of laser etching wavelength in synthesizing and characterizing silver nanoparticle (AgNPs) decorated porous silicon (PS) layers within plasmonics hybrid structure sensors. The porous silicon has been created by laser–supported etching pathway under various laser etching wavelengths of 820nm, 635nm, 536nm and 405nm with fixed laser power density (100 mW/cm²) at room temperature. Morphological, structural attributes, as well as sensing parameters of plasmonics silver nanoparticles were studied through analyses represented by Field Emission Scanning Electron Microscopy (FE-SEM), X-ray Diffraction (XRD) patterns, and Fourier Transform Infrared Spectroscopy (FTIR) results. Two distinct morphologies of bare PS, characterized by pores and island-like structures with varying shapes and surface densities, were synthesized. The results revealed a well-structured AgNPs-PS configuration structure by altering the wavelength of laser etching island-like morphologies. This resulted in a 536 nm laser wavelength, which was employed to create excellent sensing parameters of AgNPs-PS plasmonics hybrid structures. The plasmonic features, involving size distribution of hotspot regions and their geometrical shape, were expertly redesigned with the etching laser wavelengths. The histogram of the dimensions, shapes and depths for hot spot regions of AgNPs-PS created with a 536 nm laser wavelength displayed specific sensing parameters; due to the higher nanoparticle accumulation within the hot spot regions and the sharp edge boundaries of hot spot regions.</p>