Progetto comune di ricerca

Morfogenesi ottica di nanostrutture caratterizzate mediatne microscopia foto-acustica

Responsabili di progetto
Silvia Soria Huguet, Tupak Ernesto García Fernandez
Accordo
MESSICO - CONACYT - Consejo Nacional de Ciencia y Tecnologia
Bando
CNR-CONACYT 2017-2018
Dipartimento
Ingegneria, ICT e tecnologie per l'energia e i trasporti
Area tematica
Ingegneria, ICT e tecnologie per l'energia e i trasporti
Stato del progetto
Nuovo

Proposta di ricerca

The main goal of this project is the development of all-photonic technologies to synthesize, monitor the formation and analyze the principal features of metal colloids, by the combination of versatile approaches for pulsed laser generation of nanostructures and innovative photoacoustics.
The principal tasks of CNR will consist in the development and integration of an innovative acousto-optical transducer into a photoacoustic spectro-microscope for applications in life and materials sciences.
Photoacoustics implies the use of short optical pulses to trigger a cascade of photothermal and thermoelastic events, which result into the emission of shockwaves. This concept is being exploited in diverse contexts, such as noninvasive medical imaging [F. Ratto et al, Adv. Funct. Mater. DOI: 10.1002/adfm.201600836 (2016)] and material analysis [L. Cavigli et al, J. Phys. Chem. C 118, 16140-6 (2014)]. By scanning through the optical wavelength, one may gain insight into the chemical composition of specimens for e.g. molecular imaging. By analyzing the time-of-flight or the power spectrum of the ultrasound (US) emission, one may achieve depth-sectioning or the potential for particle size analysis [E.M. Strohm et al, Biophys. J. 105, 59-67 (2013)]. In the context of materials science, photoacoustics has been used to e.g. assess the composition of gases [A. Miklos et al, Rev. Sci. Instrum. 72, 1937-55 (2001)], monitor the emission of soot [W. Schindler et al., SAE Technical Paper 2004-01-0968 (2004)], quantify the photostability of metal nanoparticles [L. Cavigli et al, J. Phys. Chem. C 118, 16140-6 (2014)], address the evolution and collapse of microbubbles [M.G. González et al, Appl. Phys. Lett. 96, 174104 (2010)] and measure acoustic parameters in liquids [Z. Zhao and R. Myllylä, Appl. Opt. 51, 1061-6 (2012)]. The introduction of photoacoustics to follow the formation of metal colloids is a pioneering achievement by CONACYT [M.A. Valverde-Alva et al, Appl. Surf. Sci. 335, 341-9 (2015)].
The standard technology to detect the US emission in photoacoustics rests on piezoelectric transducers in use in US imaging. However, US imaging and photoacoustics differ in fundamental aspects. While the requirement for echographic ultrasonography is narrow-band US generation and detection, the impulsive profile of photoacoustics calls for ultra-broadband US detection to recover most info. Another goal in photoacoustics is the optical transparency of its acoustic arm, e.g. for collinear optical excitation and US collection, which is crucial for miniaturization in applications in materials science.
Optical whispering gallery mode (WGM) resonators have been proposed as a radical alternative to combine ultra-broadband and ultra-sensitive US detection, optical transparency and the promise to maintain their performance with miniaturization. These devices exploit the unique features of high quality factor optical resonant cavities made of dielectric WGM spherical resonators [A. Chiasera et al, Laser Photon. Rev. 4, 457-82 (2010)], such as their extreme sensitivity to strain, in order to analyze acoustic waves [B. Dong et al, Opt. Lett. 39, 4372-5 (2014); H. Li et al, Sci. Rep. 4, 4496 (2014); S.L. Chen et al, Photoacoustics 3, 143-50 (2015)].
We propose to investigate a similar effect on hollow WGM spherical resonators made from glass capillaries, which allow for a physical separation between the coupling platform to their outer surface and their inner cavity where liquids are confined. [S. Berneschi et al, Opt. Lett. 36, 3521-3522 (2011)]. These devices will be integrated into a unique photoacoustic spectro-microscope, tested and benchmarked with the metal colloids and methods that will be optimized at CONACYT.
The exploitation of the plasmonic features of metal colloids and thin films is emerging as a powerful strategy for applications that are as diverse as biomedicine, sensing, photovoltaics and microelectronics [N.L. Rosi and C.A. Mirkin, Chem. Rev. 105, 1547-62 (2005); H.A. Atwater and A. Polman, Nature Mater. 9, 205-13 (2010)]. Notable examples include the use of gold nanoparticles as contrast agents for photothermal treatments and photoacoustic imaging in biomedicine [F. Ratto et al, Adv. Funct. Mater. 25, 316-23 (2015); F. Ratto et al, Adv. Funct. Mater. DOI: 10.1002/adfm.201600836 (2016)].
CONACYT will develop an innovative platform to produce nanostructures including metal colloids and thin films by optical methods, such as pulsed laser deposition (PLD) and laser ablation in liquids (LAL), and monitor their formation online by standard photoacoustics. PLD and LAL rely on the interaction between short optical pulses and a target of choice, in order to trigger its ablation and transfer its stoichiometry into a thin film or a colloidal suspension with high purity.
Finally, CNR and CONACYT will collaborate towards the design of a hybrid platform integrating the components for PLD and LAL and those for photoacoustic spectro-microscopy with the innovative acousto-optical transducer from CNR, for the dynamic inspection of nanostructures during their formation. This project capitalizes on the expertise of CNR and CONACYT in:
1) LAL and PLD to fabricate nanostructures (CONACYT);
2) The use of photoacoustics to analyze metal nanoparticles (CNR and CONACYT);
3) The fabrication and inspection of WGM resonators and their integration into a variety of sensors (CNR).
Both partners perceive this project as a timely opportunity to pursue strategic developments in their respective labs, such as a unique photoacoustic spectro-microscope at CNR that will generate perspectives for external funding. The exchange of knowledge and materials between CNR and CONACYT will foster these developments and create the premise for a durable collaboration.

Obiettivi della ricerca

The principal objectives of this project include the synergistic integration of technologies between CONACYT and CNR towards:
1)Synthesis of metal nanoparticles by LAL and thin films by PLD (CONACYT);
2)Standard photoacoustics studies after their generation (CONACYT);
3)Development of a novel design of acousto-optical transducers based on WGM featuring ultra-broadband sensitivity and optical transparency (CNR);
4)Their integration into a photoacoustic spectro-microscope (CNR);
5)Assessment of their performance to analyze the metal nanoparticles in terms of optical absorbance, photostability and size (CNR);
6)Design of a hybrid setup for the synthesis of nanostructures by LAL and PLD and their online analysis by advanced photoacoustics with new acousto-optical transducers (CNR and CONACYT);
7)Exchange of knowledge and materials between CNR and CONACYT on the occasion of 4 joint seminars;
8)Training of a young scientist on WGM and photoacoustics at CNR;
9)3 bachelor theses, 1 M.Sc. thesis and 1Ph.D. project on LAL, PLD and photoacoustics under the supervision of CONACYT;
10)4 joint papers in ISI journals;
11)4 joint presentations at international conferences;
12)2 surveys on the patentability of specific solutions for the integration of LAL, PLD and photoacoustics (CONACYT) and the design of new acousto-optical transducers (CNR);
13) Submission of a H2020 proposal on the introduction of new a acousto-optical transducers into photoacoustic spectro-microscopy (CNR).