Whispering gallery modes in indium oxide hexagonal microcavities Hongxing Dong,1 Zhanghai Chen,1 Liaoxin Sun,1 Jian Lu,1 Wei Xie,1 H. Hoe Tan,2 Chennupati Jagadish,2 and Xuechu Shen1 1Department of Physics, Surface Physics Laboratory, Advanced Materials Laboratory, Fudan University,Shanghai 200433, China 2Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, canberra, Australian Capital Territory 0200, Australia Motivation (1) Whispering gallery (WG) resonators have attracted much attention due to their microscopic size, high quality factor Q, and low lasing threshold power. (2) The investigation of the nanowire WG resonators is so far limited on ZnO hexagonal resonators duo to the difficulty in synthesizing high quality microcavities with other oxide materials. (3) The application of In2O3 as optical cavities has not yet been explored. Here, we report the fabrication of high quality In2O3 nanowires with hexagonal cross section and the observation of series of WGM resonance in the wires. Experiment and Discussion Plane wave model for WGM TM polarization, β=1/n, for TE polarization, β=n. Cauchy dispersion formula n‖=1.8529+59220.04/λ2 n⊥=1.8591+64257.61/λ2 We fabricated the In2O3 nanowires with hexagonal cross section by an in situ thermal oxidation method and performed emission spectral measurements for detections of unpolarized, TM (the electrical component of light E//c-axis), and TE polarized (E⊥c-axis) signals, respectively. Conclusion we have reported the synthesis of indium oxide nanowires with hexagonal cross section and the WGM resonator characteristics of these wires. WGMs in the visible spectral range were directly observed at room temperature. We find that the In2O3 nanowire WGMs are preferentially TM polarized and the WGM peak positions can be calculated using a simple plane wave interference model and Cauchy dispersion equation. References: 1 A. C. Tamboli, E. D. Haberer, et al, Nat. photonics 1, 61 (2007). 2 T. Nobis, E. M. Kaidashev, et al, Phys. Rev. Lett. 93, 103903 (2004) 3 L. X. Sun, Z. H. Chen, et al, Phy. Rev. Lett. 100, 156403 (2008).