Medida de la dispersión cromática de una cavidad en anillo para láser de fibra óptica basado en amplificación paramétrica.

En este trabajo se va a construir un montaje experimental similar al que se necesitaría para conseguir acción láser basada en amplificación paramétrica que se produciría en una fibra altamente no lineal (HNLF). Dicho montaje estará formado por un anillo de fibra que contendrá una muestra de HNLF, la cual genera espectro supercontinuo cuando es bombeada por un tren de pulsos procedentes de un láser de fibra óptica dopada con erbio pulsado mediante mode-locking. Además, es necesario poder modificar la longitud de anillo para conseguir la coincidencia temporal entre pulsos de bombeo y pulsos de espectro supercontinuo. Para ello, formarán parte del anillo un par de colimadores GRIN enfrentados entre sí y que pueden separarse de forma controlada mediante un desplazador motorizado logrando la modificación en la longitud de anillo.También se va a determinar el índice de refracción de grupo en función de la longitud de onda (dispersión cromática) para la fibra HNLF y para el anillo completo, para lo cual será necesario caracterizar experimentalmente las diferencias de tiempos de vuelo entre los pulsos de bombeo y los pulsos de supercontinuo tras dar una vuelta al anillo.Finalmente, se analizará cómo podría llevarse a cabo la compensación de dichas diferencias temporales de forma que los dos tipos de pulso coincidan temporalmente a la entrada de la HNLF y se pueda conseguir amplificación paramétrica.<br /

Multifrequency Nanomechanical Mass Spectrometer Prototype for Measuring Viral Particles Using Optomechanical Disk Resonators

Nanomechanical mass spectrometry allows characterization of analytes with broad mass range, from small proteins to bacterial cells, and with unprecedented mass sensitivity. In this work, we show a novel multifrequency nanomechanical mass spectrometer prototype designed for focusing, guiding and soft-landing of nanoparticles and viral particles on a nanomechanical resonator surface placed in vacuum. The system is compatible with optomechanical disk resonators, with an integrated optomechanical transduction method, and with the laser beam deflection technique for the measurement of the vibrations of microcantilever resonators. The prototype allows the in-vacuum alignment of resonators thanks to a dedicated visualization system. Finally, in this work, we have demonstrated the detection of gold nanoparticles, polystyrene nanoparticles and phage G viruses with optomechanical disks and microcantilever resonators.Peer reviewe

Simultaneous optical and mechanical sensing based on nano-optomechanical disks

Resumen del trabajo presentado en la 12th International Conference on Metamaterials, Photonic Crystals and Plasmonics - META, celebrada en Torremolinos (España), del 19 al 22 de julio de 2022In this work, we demonstrate that by bringing together optical and mechanical resonances in single sensing platforms, their performances are significantly enhanced. In particular, we use nano-optomechanical disks, which simultaneously support high quality optical and mechanical modes. First, we apply the simultaneous or dual optical and mechanical sensing technique for monitoring environmental changes. Then, we employ it for detecting individual bacteria, accessing to its optical and mechanical properties. A variety of optical and mechanical resonators have been successfully employed in a diversity of sensing applications. Typically, optical resonators stand out for being extraordinary sensitive, while mechanical resonators are highly reliable. In this sense, optomechanical devices are unique platforms, since they support, at the same time, high quality optical and mechanical modes. Here we highlight the advantages of combining optical and mechanical resonances in a unique sensing platform, improving the sensor assets, together with its reliability and robustness. In particular, we apply nano-optomechanical disks fabricated out of gallium arsenide (Figure 1), which have already shown excellent capabilities when operating in liquids and for biosensing applications [1, 2]. We first apply them for monitoring environmental changes. Notably, the dual sensing approach allows decoupling relative humidity and temperature changes, reaching extraordinary precision, 0.01 % and 100 µK respectively (Figure 2). To further prove the capabilities of this novel method, we employ it for detecting individual bacteria (Figure 3). The technique allows to simultaneously access the bacterium optical and mechanical properties, such as its refractive index, absorption coefficient, mass, rigidity and viscosity [3].Work produced with the support of a 2021 Leonardo Grant for Researchers and Cultural Creators, BBVA Foundation. The Foundation takes no responsibility for the opinions, statements and contents of this project, which are entirely the responsibility of its authors. This research is also funded by the Spanish Ministry of Science under the project MicroBIOMS, reference PID2019-109765RA-I00. E.G.S. acknowledges financial support by the Spanish Science and Innovation Ministry through the Ramón y Cajal grant RYC2019-026626-I