Characteristics of the photoacoustic signal excited by an intensity-modulated continuous-wave laser

The time-domain and frequency-spectrum characteristics of the photoacoustic signal excited by an intensity-modulated continuous-wave laser were obtained by calculation based on theoretical analysis, and were also compared with the characteristics of the sound signal excited by pulsed lasers. The frequency spectrum of the photoacoustic signal excited by an intensity-modulated continuous-wave laser was distributed evenly in a wider band width, and a higher signal to noise ratio (SNR) of the sound signal was achieved by a narrowband detector compared with the SNR of the sound signal excited by pulsed lasers. In order to improve the axial resolution of the photoacoustic signal excited by a continuous-wave laser, we increased the compression ratio and compressed the pulse width of the sound signal. Compared with the high pulse energy of the pulsed laser, the lower laser power of the continuous-wave laser can load a higher power density in biological tissues without damaging the tissues within a certain time.