Reconfigurable RGB dye lasers based on the laminar flow control in an optofluidic chip.

The optofluidic dye laser serves as an important on-chip optical source in microfluidic technology for a breadth of applications. One of the ultimate goals of such a light source is an optofluidic white dye laser. However, realizing such a device has been challenging, because it is difficult to achieve simultaneous multi-wavelength lasers that span the most visible spectrum, especially on an integrated system. Here, we demonstrate white lasing in an optofluidic chip that simultaneously lases in red, green, and blue (RGB) colors inside a microfluidic channel. A Fabry-Perot cavity formed by two end-coated fibers provides the optical feedback of the laser. Easy reconfigurable emission can be obtained based on the laminar flow control. Eventually, white lasing at a low threshold was obtained when the pumping energy density is in excess of 26.1  μJ/mm2.