Principal waves in multiply connected waveguides: concentration of laser radiation on areas of subwavelength dimensions

It is demonstrated that multiply connected waveguides can be used for the localisation or concentration of electromagnetic radiation at optical frequencies on areas of subwavelength transverse dimensions. In optical microscopes this makes subwavelength resolution possible along all three spatial coordinates. The use of multiply connected waveguides of subwavelength dimensions in the interaction of matter with laser radiation can increase considerably the field intensity in an optical wave. Applications of subwavelength waveguides in submicron photolithography, nanotechnology for microelectronics, and optical data storage and retrieval are discussed.