NFT back reflection monitor for heat-assisted magnetic recording head

Abstract

Disclosed are methods and configurations for monitoring reflections in heat-assisted magnetic recording (HAMR) heads that may lead to laser instability and power variation. HAMR heads direct light emitted by a laser toward a near field transducer (NFT) for the production of plasmons that assist in data recording. A certain amount of the laser light may be reflected at or near the NFT back toward the laser, and this reflected light can cause laser instabilities over time. As a screening measure during manufacturing or assembly, or as a laser health monitoring measure during drive operation, a back reflection monitor is used to detect the intensity of a portion of the reflected light. Back reflection monitoring capability may be provided by a bolometer integrated into HAMR recording head assemblies, and optionally along with optical components and electrical circuitry that provides laser light transmission monitoring capability.

Dependencies are inferred from the claim text.