Integration of photonic and passive microfluidic devices into lab-on-chip with femtosecond laser materials processing

Femtosecond laser materials processing is a powerful method for the integration of high resolution, 3D structures into Lab-On-Chip (LOC) systems. One major application of femtosecond laser materials processing is waveguide fabrication in glass via index modification. We demonstrate the ability to fabricate couplers and Mach-Zehnder Interferometers (MZI) with good repeatability and flexibility. An in-depth characterization of the spectral characteristics of symmetric directional couplers and MZI is presented. The spectral data from a series of unbalanced MZI is used to characterize changes in the waveguide propagation constant. Towards integrated sensing, we demonstrate the application of femtosecond laser waveguide fabrication to the integration of a MZI into a homemade and commercial LOC for label-free optical detection. The MZI has a unique tilted 3D geometry with one arm crossing a microfluidic channel and enables spatially resolved sensing of changes in the refractive index of the content inside the channel with a limit of detection as low as 1x10 4 RIU. Another major technique in femtosecond laser materials processing is femtosecond two-photon polymerization (TPP). TPP is used to integrate 3D porous filters into a commercial LOC and testing of the filter shows virtually 100% efficient separation of 3 tm polystyrene spheres from a liquid solution. The direct write and maskless nature of femtosecond materials processing makes it a powerful method to integrate 3D devices into LOC without altering existing elements or changing the microfluidic channel fabrication.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2011

Author dc:creator

• Gu, Yu, Ph.D. Massachusetts Institute of Technology

Advisor dc:contributor.advisor

• James G. Fujimoto.

• Electrical Engineering and Computer Science.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/66004

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/66004