An all-fiber component capable of sorting and counting microparticles based on size is presented. A sequence of silica fiber capillaries were used to fabricate the component for separation and detection. The portable, lab-scale “all-fiber” device was fabricated by assembling different silica fiber capillaries and optical fibers in a Vytran glass processing station. We report elasto-inertial microfluidics based particle migration and focusing and demonstrate high separation efficiency between 10 µm (100%) and 1 µm (97%) microparticles. The separated 10 µm particles were further analyzed for counting in the integrated fiberoptics component at a speed of ~1400 particles/min.

n all-fiber separation component capable of sorting and counting micron-sized particles based on size is presented. A sequence of silica fiber capillaries with various diameters and longitudinal cavities were used to fabricate the component for separation and detection in an uninterrupted flow. Fluorescence microparticles of 1 μm and 10 μm sizes are mixed in a visco-elastic fluid and infused into the all-fiber separation component. Elasto-inertial forces focus the larger particle to the center of the silica capillary, while the smaller microparticles exit from a side capillary. Analysis of the separated particles at the output showed a separation efficiency of 100% for the 10 μm and 97% for the 1 μm particles. In addition, the counting of the larger particles is demonstrated in the same flow. The separated 10 μm particles are further routed through another all-fiber component for counting. A counting speed of ~1400 particles/min and with the variation in amplitude of 10% is achieved. A combination of separation and counting can be powerful tool may find several applications in biology and medicine, such as separation and analysis of exosomes, bacteria, and blood cell sub-populations.

Using various fiber capillaries with different diameters and multiple holes we develop an optofluidic component capable of separating micron-sized beads emulating cells and bacteria, exploiting particle focusing in a viscoelastic fluid and analyzed optically.

A fiber probe traps single micrometer-particles by fluid suction into a hollow microstructure and enables optical identification by the fluorescence light collected in a fiber core. The probe finds applications in life-science and environmental monitoring.

A fiber probe traps single micrometer-particles by fluid suction into a hollow microstructure and enables optical identification by the fluorescence light collected in a fiber core. The probe finds applications in life-science and environmental monitoring.

We demonstrate the digital electric field induced switching of plasmonic nanorods between "1" and "0" orthogonal aligned states using an electro-optic fluid fiber component. We show by digitally switching the nanorods that thermal rotational diffusion of the nanorods can be circumvented, demonstrating an approach to achieve submicrosecond switching times. We also show, from an initial unaligned state, that the nanorods can be aligned into the applied electric field direction in 110 ns. The high-speed digital switching of plasmonic nanorods integrated into an all-fiber optical component may provide opportunities for remote sensing and signaling applications.

A fiber probe is presented that traps single micro-sized particles and allows detection of their optical properties. The trapping mechanism used is based on fluid suction with a micro-structured optical fiber that has five holes along its cladding. Proof-of-principle experiments with a diluted solution of fluorescently labeled particles are performed. The fiber probe presented here may find various applications in life-science and environmental monitoring.  

Flow cytometry is currently the gold standard for analysis of cells in the medical laboratory and biomedical research. Fuelled by the need of point-of-care diagnosis, a significant effort has been made to miniaturize and reduce cost of flow cytometers. However, despite recent advances, current microsystems remain less versatile and much slower than their large-scale counterparts. In this work, an all-silica fibre microflow cytometer is presented that measures fluorescence and scattering from particles and cells. It integrates cell transport in circular capillaries and light delivery by optical fibres. Single-stream cell focusing is performed by Elasto-inertial microfluidics to guarantee accurate and sensitive detection. The capability of this technique is extended to high flow rates (up to 800 mu l/min), enabling a throughput of 2500 particles/s. The robust, portable and low-cost system described here could be the basis for a point-of-care flow cytometer with a performance comparable to commercial systems.

Optofluidic all-fiber devices are used for orientation of Au-nanorods under strongelectric fields. The dynamics is studied on sub-microsecond time-scales. A two-level laser rateequation model allows inferring diffusion rate, rotational mobility and other parameters.

As information technologies move from electron-to photon-based systems, the need to rapidly modulate light is of paramount importance. Here, we study the evolution of the electric-field-induced alignment of gold nanorods suspended in organic solvents. The experiments were performed using an all-fiber optofluidic device, which enables convenient interaction of light, electric fields, and the nanorod suspension. We demonstrate microsecond nanorod switching times, three orders of magnitude faster than a traditional Freederickcz-based liquid crystal alignment mechanism. We find that the dynamics of the alignment agrees well with the Einstein-Smoluchowski relationship, allowing for the determination of the rotational diffusion coefficient and polarizability anisotropy of the nanorods as well as the effective length of the ligands capping the nanorods. The ability to dynamically control the optical properties of these plasmonic suspensions coupled with the point-to-point delivery of light from the fiber component, as demonstrated in this work, may enable novel ultrafast optical switches, filters, displays, and spatial light modulators.