Thermoelastic expansion vs. piezoelectricity for high-frequency, 2-D arrays

Optoacoustic generation of high frequency sound for 3-D ultrasonic imaging in medicine

“…Efficiency is defined as the acoustic power, calculated from the acoustic pressure estimated above, divided by the input optical power. At the low powers reported previously, the transduction efficiency was about 10 −6 [6]. Here, the efficiency is about 1.7%.…”

Optical generation of high frequency ultrasound using two-dimensional gold nanostructure

“…A promising alternative is an optoacoustic array relying on optical generation and detection of ultrasound. [5][6][7][8][9] These arrays use two laser beams, one for generation and the other for detection. Their size and location define transmit and receive elements.…”

“…We have previously shown that the transduction efficiency can increase by 30 dB using an 11 m thick spin-cast film consisting of a mixture of carbon black and polydimethylsiloxane ͑PDMS͒. [5][6][7][8] This device can produce acoustic power comparable to an ideal piezoelectric element at frequencies in the 100 MHz regime. 6 The bandwidth of the generated ultrasound is mainly limited by the thickness of the acoustically absorbing PDMS film.…”

“…[5][6][7][8] This device can produce acoustic power comparable to an ideal piezoelectric element at frequencies in the 100 MHz regime. 6 The bandwidth of the generated ultrasound is mainly limited by the thickness of the acoustically absorbing PDMS film. The optical absorption depth of the black PDMS film defines the size of the acoustic source, which is estimated to be about 1 m from the substrate based on the shape of the acoustic radiation pattern.…”

3D printed photoacoustic shockwave transducer for cavitation research

“…There are different mechanisms to generate ultrasound, including piezoelectricity, and photoacoustics [7]. Piezoelectricity is the most common approach to produce high frequency ultrasound below 10 MHz [11]. The piezoelectric transducer responds to the AC voltage.…”