Integrated All-In-Silica Optofluidic Platform Based on Microbubble Resonator and Femtosecond Laser Written Surface Waveguide

• Type: Article in International Scientific Journal
• Date: 2024

Authors

Amorim, VA (Author) Other; Frigenti, G (Author) Other; Baldini, F (Author) Other; Berneschi, S (Author) Other; Farnesi, D (Author) Other; Jorge, PAS (Author) FCUP; Maia, JM (Author) Other; Conti, GN (Author) Other; dos Santos, PSS (Author) Other; Marques, PVS (Author) FCUP

Journal

Title: IEEE Sensors Journal

Vol. 24

ISSN: 1530-437X

Publisher: IEEE

Indexing

ISI Web of Knowledge - 0 Citations

Scopus - 0 Citations

Other information

Authenticus ID: P-011-6PS

DOI: 10.1109/jsen.2024.3418203

Abstract (EN): Optical microbubble resonators (OMBRs)-understood as localized thin wall bulges induced in silica microcapillaries-are gaining an ever-growing interest in microfluidic sensing applications due to their capability to sustain whispering gallery modes (WGMs) and confine the fluidic sample within their own hollow-core microcavity. Currently, most applications use an external tapered optical fiber for coupling light to the resonator. This arrangement is known to be fragile and prone to vibrations. In this work, an alternative approach, based on coupling OMBR with a femtosecond (fs) laser-written optical waveguides, integrated at the surface of fused silica substrate, is proposed. In this configuration, a stable and robust final structure is accomplished by gluing the two ends of the microcapillary, on which the OMBR is made, to the substrate. The OMBR quality factors, measured at the excitation wavelength of 1540 nm, show values close to 10(4) in the case of a water-filled cavity, with a maximum coupling efficiency of up to 6.5%. Finally, the operation of the integrated optical devices as refractometers is demonstrated by delivering different solutions with successively increasing concentrations of NaCl inside the OMBR. An average sensitivity of 45 nm/RIU is obtained, yielding a resolution of 4.4x10(-5) RIU, creating the potential for this platform to be applied in chemical/biochemical sensing.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8