Trapping light into high orbital momentum modes of fiber tapers

A tapered cylindrical dielectric optical waveguide acts as a high quality factor white-light cavity providing high field concentration as well as long optical group delay. It is possible to optimize shape of a lossless taper to suppress reflection of the input light and to achieve infinitely high field concentration. These tapers can be used in sensing and optoelectronics applications instead of conventional microcavities.