Integration of 3D micro-optics and microfluidics in a glass chip using a femtosecond laser for photonic applications

We describe a 3D microprocessing for directly forming microoptics buried in a glass chip using a femtosecond (fs) laser irradiation followed by postannealing and successive chemical etching. By forming hollow internal structures with smooth surfaces inside glass, a variety of 3D microoptical components, such as micromirror, microbeam splitter, and microoptical circuit have been embedded in the glass and their optical properties were interrogated at the communication wavelength of 1550nm. The micromirror can reflected the light beam at 90 degrees by a total internal reflection with an optical loss of only 0.24dB. The 3D microoptics can then be integrated with 3D microfluidics for producing functional devices. Herein, we demonstrate the fabrication of microfluidic dye lasers and test the lasing functions. After filling the microfluidic chamber with a laser dye rhodamine 6G dissolved in ethanol and pumping the microfluidic laser by a frequency-doubled Nd:YAG laser, lasing action was confirmed by analyzing the emission spectra at different pumping powers. Furthermore, use of such a true 3D processing also enables fabrication of devices with multi-layered configuration. By serially embedding two microfluidic chambers in the glass, we built a microfluidic twin-laser which produces array of simultaneous two laser emissions using one pumping laser. The integration of 3D microoptics and microfluidics into the single glass chips opens up the possibility of automatic manufacture of hybrid devices for photonic applications.