Sensitive optomechanical ultrasound sensor in an LED-based, low fluence photoacoustic imaging system

Affordable and compact light sources, along with highly sensitive, broadband, low-noise sensors, are essential for enabling point-of-care photoacoustic imaging applications in resource-limited settings. Traditional systems use piezoelectric transducers, which often suffer from limited bandwidth and sensitivity, combined with solid-state lasers that are expensive and bulky. We present a potentially low-cost LED-based photoacoustic imaging system featuring a highly sensitive optomechanical ultrasound sensor operating near thermomechanical noise limits. Utilizing a 620 nm LED, our setup delivers microjoules of pulse energy with 100 ns pulse widths. We demonstrate its capability to resolve fine details through 2D scan tomography, with minimal averaging for an effective sample rate of 100 Hz. Future improvements, including the development of larger LED arrays, multiplexed sensors and on-chip integrated lasers, promise to enhance performance and further expand the technology's applicability