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OF3: Optofluidics: Optofluidics Imaging, Trapping, and Spectroscopy
8:30 - 10:00
Session Chair: Kevin K. Tsia, The University of Hong Kong
Location:Room 22a, 2nd floor, ICM Light Engineering and Optofluidics
8:30 - 8:45
Droplet-based microlenses actuated by laser-induced solutocapillary forces
Aleksandr Malyuk, Natalia Ivanova
Tyumen State University, Russian Federation
A tunable liquid lens based on laser induced solutocapillary effect is presented. Our lens behaves similar to the pupillary light reflex that controls its diameter and surface curvature in response to the intensity of light. It is capable to change its focal length in range from infinity to 22 mm and change position on a glass substrate toward a laser beam. Solution of ethylene glycol and ethyl alcohol in three different mass fraction investigated as a base liquid for lens creation.
8:45 - 9:00
Microfluidic velocity measurement using dual-plane optical coherence tomography imaging
Evangelos Rigas, Jonathan Mark Hallam, Helen Ford, Tom Charrett, Ralph Tatam
Centre for Engineering Photonics, Cranfield University, United Kingdom
A novel dual-beam optical coherence tomography (OCT) system for imaging and velocity measurement of micrometre diameter particles in microfluidic flows has been created, and the first results from this system are presented. This system requires only a single optical access port and can in principle obtain 2- or 3- velocity-components.
9:00 - 9:15
Investigation of microfluidic particles motion by 3D holographic tracking
Pasquale Memmolo, Teresa Cacace, Melania Paturzo, Martina Mugnano, Francesco Merola, Lisa Miccio, Pietro Ferraro
CNR Institute of Applied Sciences and Intelligent Systems, Italy
Nowadays, digital holography (DH) in microscopy is one of the most used imaging instrument to the microfluidics investigation at lab-on-chip scale. One of the amazing property of DH is the capability to calculate a posteriori the focal plane of imaged objects by numerical processing. This allows accurate retrieving of the 3D positions of multiple particles during their motion in a microfluidic device, performing 3D tracking in the entire field of view. Thank to this feature, several holographic-based tracking methods have been proposed in literature for characterization of particles migration in microfluidics. In this paper, we compare several 3D holographic tracking methods, implemented to investigate three different experimental conditions, i.e. microfluidic-induced particle migration, free-flowing particles and particles manipulation.
9:15 - 9:30
Silicon Photonic Tweezers: from Trapping Potential Analysis to Photonic and Microfluidic Applications
Christophe Pin1,3,4, Claude Renaut1,3,4, Emmanuel Picard3, David Peyrade2,4, Emmanuel Hadji3, Frédérique de Fornel4, Benoît Cluzel1
1Université de Bourgogne - Franche Comté, France; 2Université Grenoble Alpes, France; 3CEA Grenoble, France; 4CNRS, France
We study here the trapping of dielectric microparticles of different size using a silicon photonic crystal nanocavity. Applications such as optofluidic near-field optical microscopy and on-chip assembly of articulated microtools are also introduced.
9:30 - 9:45
Optimization of Micro-Optical Dimensions for Enhancing Sensitivity in Integrated Microfluidic Laser-Induced Fluorescence Detection
Debbie Lo, Lothar Lilge
University of Toronto, Canada
To date, detecting the lower limit of the biologically relevant dynamic range still involves maximizing the collection efficiency of fluorescence coupled into off-chip confocal set-ups. However, towards integrated microfluidic laser induced fluorescence (LIF) detection, detector dimensions should be considered in addition to the collection efficiency when arranging micro-optical components. As a proof-of-concept microfluidic LIF-CE detection module, a micro-ball lens embedded in carbon-blackened PDMS filter is used to couple fluorescence to an on-chip CMOS detector to achieve a 17-fold increase in SNR. By further optimizing detector element dimensions, an additional 2-fold increase in SNR was achieved.
9:45 - 10:00
Resonance Raman spectroscopy and cell-free volume creation in microfluidic channels
Moritz Matthiae, Xiaolong Zhu, Rodolphe Marie, Anders Kristensen
Denmarks Technical University (DTU), Denmark
Due to the uniqueness of molecular vibration, the selectivity of Raman spectroscopy is dependable. Raman scattering intensity can be enhanced by means of resonance Raman spectroscopy where the laser excitation frequency is chosen corresponding to an electronic transition of the molecule under study. We demonstrate resonance Raman spectroscopy in microfluidic channels for the analysis of turbid media. As an example, we detect hemoglobin in bovine blood plasma. Furthermore, we investigate the creation of cell-free regions for in-line Raman spectroscopy in microfluidic flow of liquid suspensions. A specific microfluidic design for hydrodynamic particle filter functionality is presented.