High Quality Direct Photo-patterned Microdisk Lasers with Organic/Inorganic Hybrid Materials

Optical microcavities are widely studied because they have many applications in fundamental physics, nonlinear optics, optical communication, and bio-sensing. At present, microcavity materials can be classified as two families: inorganic and organic materials. Organic microcavities usually have much lower cavity quality Q value, mostly due to the difficulties in obtaining very smooth cavity boundaries even with proper thermal reflow after complex patterning process. Luminescent conducting polymers and dye-doped polymer 2-D microdisk lasers with different shapes were created by microlithography and 02 reactive ion etching steps. So far the achieved Q values from organic microdisk lasers are between several hundred and 10000. Recently, the sol-gel technology based on the wet processes at low temperature has proven to be one promising approach to produce low-cost organic-inorganic integrated optical devices. Photosensitive organic-inorganic hybrid materials can be applied for direct photo-fabrication of optical waveguide devices. Their optical properties such as refractive index can be precisely controlled by selecting the functionality of organic constituents and metal oxide composition. In this work, sol-gel organic-inorganic hybrid microdisk-on-chip technique based on the direct UV patterning and wet etching was used to fabricate microdisk lasers on silicon substrate. One-step patterning produces high quality microlaser arrays for experimental study. Moreover, it was found that a thin polymer cladding on the microdisk can obviously improve the cavity boundary smoothness and thus increase the Q value of the cavity to as high as 12000.