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Distributed Feedback Laser Biosensors

We are developing a new label free biosensor system using a vertically-emitting distributed feedback (DFB) laser. The DFB laser sensor represents a departure from conventional high Q factor passive resonant optical sensors to improve the sensor detection limit. In a collaboration with Prof. J. Gary Eden and Dr. Clark Wagner in the Electrical and Computer Engineering Department at UIUC, we are building DFB laser sensor actively generates its own narrowband high intensity output, the system has no stringent requirements for light coupling alignment resulting in a simple, robust illumination and detection configuration.  The project is supported by SRU Biosystems and NSF.

Schematic diagram of the sensor structure and experimental setup.

DFB laser biosensor incorporated with bottomless 96-well microplate (under UV lamp).

Spontaneous emission and laser spectra for the DFB laser recorded for pump fluences below and above threshold. The inset displays the dependence of the relative laser output power on the pump fluence. Observed laser spectrum when the sensor surface is immersed in DI water.

The kinetic detection of wavelength shift of the streptavidin immobilizationand the biotin binding with the streptavidin process.

References:

1. "Vertically emitting, dye-doped polymer laser in the green (lambda ~ 536 nm) with a second order distributed feedback grating fabricated by replica molding," M. Lu, J.G. Eden, and B.T. Cunningham, Optics Communications, Vol. 281, p. 3159-3162, 2008.

2. "Label free biosensor incorporating a replica-molded, vertically emitting distributed feedback laser," M. Lu, S. S. Choi, C. J. Wagner, J. G. Eden, and B. T. Cunningham, Applied Physics Letters, Accepted, April, 2008.

3. "Vertically emitting distributed feedback laser for active label free biosensing," M. Lu, S. Choi, C.J. Wagner, J.G. Eden, and B.T. Cunningham, Conference on Lasers and Electro Optics, San Jose, CA, May, 2008.