Laser ultrasound emitter using low cost and compact high power diode laser for ultrasound biomedical imaging

Abstract

Medical ultrasound is an imaging technique that utilizes ultrasonic signals as information carriers, and has wide applications such as seeing internal body structures and finding the sources of an internal diseases. The most used ultrasonic transducer today is based on piezoelectricity. The piezoelectric transducer, however, may have a limited bandwidth and insufficient sensitivity for reduced element size. In this work we demonstrate the generation of wideband ultrasound pulses using high power diode lasers (HPDLS), short pulsed current sources and composite absorbers. We design and implement the pulsed current sources optimized for the HPDLs. We fabricate candle soot-PDMS composite targets. We have achieved peak pressure of 323 kPa and bandwidths at -6 dB of 34 MHz using a diode laser with an optoacoustics conversion efficiency of 5.3 * 10 -3 Pa/(W/m 2 ). Finally, we present a compact low-cost tunable ultrawideband laser ultrasound emitter.