20.500.12556/RUL-178476 Ultrafast subwavelength CVD-graphene nanoheater for the generation of broadband photoacoustic waves Efficient operation of light-to-pressure transducers and flexible fabrication on demand are key factors for the use of photoacoustic devices in various biomedical disciplines. Graphene layers can be grown at wafer scale and transferred to any surface geometry, providing a versatile approach for the development of photoacoustic emitters with a large and nearly uniform thermal interface. Here we report the picosecond excitation of a photoacoustic emitter consisting of a large-area, 10-layer graphene grown by chemical vapour deposition and encapsulated with a polydimethylsiloxane. The theoretical and experimental studies address the generation of broadband ultrasounds upon excitation with nanosecond and picosecond laser pulses, showing how the multilayer graphene can serve as an ultrafast nanoheater to drive efficient expansion of the adjacent polymer layer in the picosecond regime. The picosecond excitation results in a sharper acoustic waveform, and the pressure evolution time is twice as short with a 30 ps excitation as with a 6 ns pulse, thus satisfying the thermal and stress confinement conditions, while energy loss occurs with nanosecond excitation. We experimentally observed that the 10-layer graphene/polydimethylsiloxane generates a high-frequency photoacoustic wave with a bandwidth of about 110 MHz at −6 dB, increasing to 250 MHz at −20 dB, due to stress confinement, increased thermal interface, and ultrafast dynamics. The peak pressure of 0.85 MPa in 3.4 nm thick graphene multilayers (∼20 % absorption of 40 mJ cm▫$^{-2}$▫) is remarkably high, demonstrating its potential as a photoacoustic material and the advantages of combining picosecond excitation with large-area graphene in wave transmission technologies. CVD-graphene photoacoustic emitter picosecond photoacoustic high-frequency ultrasound photoacoustic wave laser-generated ultrasound ultrafast nanoheater true false true Angleški jezik Angleški jezik Članek v reviji 2026-01-28 14:00:18 2026-01-28 14:00:19 2026-01-30 04:14:52 0000-00-00 00:00:00 2026 0 0 12 str. art. 100796 Vol. 47 2026 0000-00-00 Zaloznikova Objavljeno apc 0000-00-00 0000-00-00 0000-00-00 534 2213-5979 10.1016/j.pacs.2026.100796 266484227 https://www.sciencedirect.com/science/article/pii/S2213597926000029?via%3Dihub 1 4715308e-fc49-11f0-a1ba-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=226372 https://www.sciencedirect.com/science/article/pii/S2213597926000029?via%3Dihub 1 405a5752-fc4a-11f0-a1ba-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=226373 RAZ_Rezaei_Ali_2026.pdf RAZ_Rezaei_Ali_2026.pdf 1 026AEAC58465EA5E114019AD7CBABD9C 6fd26891348520eaaa7f238311326219ef639c5903642fe353d98c824c17f84f 9d3858f9-fc4a-11f0-a1ba-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=226374 Fakulteta za strojništvo 0 0 0