Over recent years, photoacoustic concepts have drawn much attention for new applications and innovative solutions in biomedical optics. In particular, photoacoustic imaging is penetrating the clinical arena as a non-invasive and versatile solution to combine optical contrast and ultrasonic depth of penetration and scalability of resolution. [1,2] The peculiar features of photoacoustic imaging have been demonstrated in a notable variety of setups, ranging from microscopy to tomography, that are already mature and competitive for translational developments. Most photoacoustic platforms rely on piezoelectric transducers that were developed within the venerable context of ultrasonography. However, the generation and propagation of acoustic signals in photoacoustics and ultrasonics differ in fundamental aspects that deserve innovative solutions and yield new opportunities. Here, we disclose our design and preliminary results for an all-optical photoacoustic flow spectro-cytometer that may be exploited in a broad variety of applicative domains, such as the detection of individual circulating cells in bio fluids as well as the inspection of colloidal suspensions of artificial particles in sols or aerosols. This setup rests on the implementation of an optical microcavity resonator [3] that may be coupled to a microfluidic interface and filled with any sample of interest. Then, its excitation with short optical pulses triggers a photoacoustic conversion within the cavity, which imparts a transient deformation of the glass resonator and its dielectric landscape, thus shifting its optical resonances. The advantages of this setup include its inherent feasibility for miniaturization and workability in air rather than water, as occurs with piezoelectric transducers for ultrasonography. We illustrate these features in the analysis of the spectral fingerprints of colloidal suspensions of plasmonic particles with volumes in the nL range and repetition rates in the kHz domain. We gratefully acknowledge funding from the bilateral project CNR-CONACYT (2017-2019, "All optical morphogenesis of nanostructures characterized by photo-acoustic microscopy").
Design of an all-optical photoacoustic platform for the inspection of plasmonic particles
Fulvio Ratto;Silvia Soria;Lucia Cavigli;Gabriele Frigenti;Filippo Micheletti;Sonia Centi;Roberto Pini
2018
Abstract
Over recent years, photoacoustic concepts have drawn much attention for new applications and innovative solutions in biomedical optics. In particular, photoacoustic imaging is penetrating the clinical arena as a non-invasive and versatile solution to combine optical contrast and ultrasonic depth of penetration and scalability of resolution. [1,2] The peculiar features of photoacoustic imaging have been demonstrated in a notable variety of setups, ranging from microscopy to tomography, that are already mature and competitive for translational developments. Most photoacoustic platforms rely on piezoelectric transducers that were developed within the venerable context of ultrasonography. However, the generation and propagation of acoustic signals in photoacoustics and ultrasonics differ in fundamental aspects that deserve innovative solutions and yield new opportunities. Here, we disclose our design and preliminary results for an all-optical photoacoustic flow spectro-cytometer that may be exploited in a broad variety of applicative domains, such as the detection of individual circulating cells in bio fluids as well as the inspection of colloidal suspensions of artificial particles in sols or aerosols. This setup rests on the implementation of an optical microcavity resonator [3] that may be coupled to a microfluidic interface and filled with any sample of interest. Then, its excitation with short optical pulses triggers a photoacoustic conversion within the cavity, which imparts a transient deformation of the glass resonator and its dielectric landscape, thus shifting its optical resonances. The advantages of this setup include its inherent feasibility for miniaturization and workability in air rather than water, as occurs with piezoelectric transducers for ultrasonography. We illustrate these features in the analysis of the spectral fingerprints of colloidal suspensions of plasmonic particles with volumes in the nL range and repetition rates in the kHz domain. We gratefully acknowledge funding from the bilateral project CNR-CONACYT (2017-2019, "All optical morphogenesis of nanostructures characterized by photo-acoustic microscopy").I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
