High-purity Semi-Insulating (HPSI) 4H-Silicon Carbide (SiC) is a leading candidate for microwave power, radio-frequency, and high-frequency wireless communication devices, owing to its wide-bandgap, high thermal conductivity, and excellent resistivity. This study introduces a novel laser-induced doping technique to enhance the electrical and optical characteristics of HPSI 4H-SiC. A pulsed Nd:YAG laser (λ = 1064 nm) was used to facilitate doping, with n-type α-SiC nanoparticle thin films of varying thicknesses deposited onto the SiC substrates as sacrificial layers to improve laser energy absorption. During irradiation, samples were immersed in an aqueous boric acid solution to enable boron incorporation into the SiC substrates. A heat-transfer model guided the selection of laser processing parameters, ensuring substrate integrity by maintaining the temperature below the peritectic limit of SiC. Secondary ion mass spectrometry (SIMS) confirmed successful boron hyper-doping of the SiC substrates. Absorption models developed in this study revealed modifications in the refraction index (n) and attenuation index (k) across the mid-infrared spectrum (λ = 3‒5 μm). Fourier-transform infrared (FTIR) spectroscopy demonstrated decreased transmittance and reflectance, alongside enhanced absorptance over the entire spectral range. Notably, a distinct absorption peak at λ = 3.12 μm was attributed to a boron-induced acceptor level at 0.39 eV. This laser-based doping technique effectively incorporated boron into HPSI 4H-SiC, altering its optical and structural properties without compromising substrate integrity. The process offers a scalable, ambient-temperature, and mask-free approach for localized doping of wide-bandgap semiconductors with significant potential for next-generation electronic and optoelectronic applications.