Ba_0.9Sr_0.1TiO₃-based optical microcavities fabricated by chemical solution deposition

Single or coupled optical microcavities have been prepared by inserting one or two dense Ba_0.9Sr_0.1TiO₃ layers, respectively, in the quasiperiodic Ba_0.9Sr_0.1TiO ₃ multilayers fabricated based on phase separation. The single microcavities exhibit well-defined resonant modes in the investigated wavelength range with a quality factor no less than 60. The resonant frequency of the mode can be tuned through varying the spinning rate during the spin-coating process to change the thickness of the inserted layer. The mode properties of the coupled microcavities strongly depend on the mismatch parameter of the inserted defect layers. The approach reported here offers a simple, inexpensive, and flexible route for fabricating high quality microcavities.