Features of the Frequency- and Time-Domain Photoacoustic Modalities

This article presents an instrumentation and modality-based study of the salient differences between pulsed and frequency-domain photoacoustic (PA) signals with respect to signal processing and imaging properties. The parameters of both modalities were adjusted to achieve the maximum signal-to-noise ratio (SNR). Experiments were performed by employing a dual-mode PA system and under the condition of maximum permissible exposure for both modalities. In addition, proper filtering has been applied post-processing to enhance the image quality for both methods. Theoretical estimates versus practical issues are discussed. In conclusion, it has been shown that parameters of these two methods can be adjusted to provide a competitive SNR and resolution.