Portable Nd:<scp>YAG</scp> Laser‐Enhanced Photoacoustic Spectral Sensing for Breast Tissues: Toward Oncological Theranostics

A solid-state laser is preferred for generating light in a photoacoustic (PA) system because of its high energy and coherence. However, conventional Nd:YAG lasers are bulky, complex, and expensive. This article introduces a portable alternative: a custom-built Nd:YAG laser with an in-house power supply that delivers 0-30 A current pulses with a 1500 μs pulse width, providing efficient thermal management. A pockels cell driver generates 10 ns pulses with 3.84 mJ/cm ² laser energy density. Implemented for noninvasive breast cancer diagnosis, The peak frequency obtained from three different samples was 0.23 ± 0.1, 0.26 ± 0.13, and 1.80 ± 0.14 MHz, respectively, for Normal, Fibrotic, and Tumor tissues. In addition to the dominant frequency peaks the spectral energy of the PASR spectra has also been investigated to characterize the breast tissue samples. The developed laser successfully differentiates between carcinoma, fibrocystic disease, and normal breast tissue based on quantitative PA spectral parameters.