Silica optical resonators with high quality factors, small mode volumes, and high refractive index contrast are desirable in many applications throughout the fundamental and applied sciences. However, these parameters are not easily modified in plain silica devices. In the present work, we theoretically and experimentally demonstrate the use of high refractive index sol-gel coatings to achieve a significant reduction in mode volume of silica toroids while maintaining high quality factors. In addition to tuning the mode volume, the presence of the coating changes both the location and shape of the optical field.
© 2012 Optical Society of America
Original Manuscript: April 24, 2012
Revised Manuscript: May 24, 2012
Manuscript Accepted: May 24, 2012
Published: July 10, 2012
Ashley J. Maker, Brian A. Rose, and Andrea M. Armani, "Tailoring the behavior of optical microcavities with high refractive index sol-gel coatings," Opt. Lett. 37, 2844-2846 (2012)