System and method of diffractive focusing of light in a waveguide

摘要

A focusing structure including an array of localized optical alterations that alter the propagation of light through the waveguide to diffractively focus the light as it exits the focusing structure. The array of optical alterations may be formed along either a straight or a curved line within a cross section of the focusing structure. In energy assisted magnetic recording apparatus a laser beam propagates through the waveguide to a near field transducer. The waveguide comprises a focusing element that includes an array of localized optical alterations that alter the propagation of the laser beam through the waveguide to diffractively focus the laser beam approximately at the near field transducer.

主权项

1. An energy assisted magnetic recording apparatus comprising:
a waveguide; a near field transducer excited by a laser beam received through the waveguide, a focusing element comprised in the waveguide, the focusing element including:
an array of localized optical alterations that alter the propagation of the laser beam through the waveguide to diffractively focus the laser beam approximately at the near field transducer, the localized alterations in the array spaced by unaltered portions of the waveguide, wherein the laser beam propagates through the array of localized optical alterations in a direction toward the near field transducer such that a portion of the laser beam is transmitted through the optical alterations and a different portion of the laser beam is transmitted through the unaltered portion of the waveguide in the direction toward the near field transducer.