Three-dimensional Mach-Zehnder interferometer in a microfluidic chip for spatially-resolved label-free detection.
Ultrafast laser writing of waveguides in glasses is a very flexible and simple method for direct on-chip integration of photonic devices. In this work we present a monolithic optofluidic device in fused silica providing label-free and spatially-resolved sensing in a microfluidic channel. A Mach-Zehnder interferometer is inscribed with the sensing arm orthogonally crossing the microfluidic channel and the reference arm passing over it. The interferometer is integrated either with a microchannel fabricated by femtosecond laser technology or into a commercial lab-on-chip for capillary electrophoresis. The device layout, made possible by the unique three-dimensional capabilities of the technique, enables label-free sensing of samples flowing in the microchannel with spatial resolution of about 10 microm and limit of detection down to 10(-4) RIU.
Crespi
Andrea
A
Istituto di Fotonica e Nanotecnologie-CNR, Dipartimento di Fisica-Politecnico di Milano, Piazza L. da Vinci, 32, 20133, Milano, Italy.
Gu
Yu
Y
Ngamsom
Bongkot
B
Hoekstra
Hugo J W M
HJ
Dongre
Chaitanya
C
Pollnau
Markus
M
Ramponi
Roberta
R
van den Vlekkert
Hans H
HH
Watts
Paul
P
Cerullo
Giulio
G
Osellame
Roberto
R