A low-threshold, high-efficiency microfluidic waveguide laser

Summary

The device is capable of producing coherent light using a non-resonant photonic pathway utilizing liquids as core and cladding. The two fluids are not mixed due to immiscibility and/or laminar flow within the channel and the differences in refractive index between the two liquids keeps the light in the inner core. This specific design is highly dynamic and the device can thus be reconfigured and adapted continuously in ways that are not possible with solid-state waveguides. By manipulating the rate of flow and the composition of the liquids the characteristics of the optical system and the laser as such can continuously be modified.

Advantages include:
-It is possible to continuously change the properties of the liquid core and cladding to change the properties of the waveguide and laser.
-Small (100 microns) and easily fabricated channels. Solid-state devices require the use of high-resolution lithography tools to generate features with the lateral dimensions necessary for single-mode waveguiding.
-The fluid flows at low Re generate an intrinsically optically smooth interface between the liquid cure and liquid cladding.

Applications

A common type of optical waveguides has been optical fibers which have been used to guide electromagnetic waves in the optical spectrum. They are mainly used as components in integrated optical circuits or as a transport medium in distant communication systems. A typical optical fiber consists of an inner solid glass core and an outer cladding with a refractive index lower than the core causing light to propagate throughout the fiber. Variations of the waveguide have emerged that include a liquid core and cladding, the subject of the patent filing, Harvard Case 2336, "Microfluidic liquid-core, liquid-cladding optical waveguides". While these devices represent significant advances in optical waveguides improvements are still needed. The invention provides a method of establishing lasing radiation through a liquid waveguide in a microfluidic device.

The technology could be used as a light source on lab-on-a-chip systems. The waveguide laser has potential benefits in various sensing applications where it is particularly well suited for biological applications.

Additional Information:

Intellectual Property Status: An international PCT patent application, WO 2006/086551, has been filed by Harvard University and is pending.

Publication:
Whitesides, M. G. et al. 2005, "A Low-Threshold, High-Efficiency Microfluidic Waveguide Laser" Journal of the American Chemical Society, 127 (25), 8952 -8953

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