Low order modes in microcavities based on silicon colloids

[EN] Silicon colloids based microcavities, with sphere size between 1 and 3 micrometers, have been synthesized and optically characterized. Due to both the small cavity volume and the high refractive index of silicon we are able to tune resonances with extremely low mode index, whose electric field distribution resembles those of electronic orbitals. The value of some parameters such as quality factor Q, effective mode volume, and evanescent field have been calculated for several modes. This calculation indicates silicon colloids can be a serious strategy for developing optical microcavities where may coexist both optical modes with large evanescent fields useful for sensing applications, as well as modes with high Q/V ratio values, of the order of 10(9)(lambda/n)(-3). (C) 2011 Optical Society of America