Reflective feedback probe for optical near-field detection

摘要

To achieve high bandwidth NSOM reflection-mode detection, we have developed a system in which the tip and aperture region of an NSOM probe serves as one end reflector of an optical cavity that includes an optically emissive medium. (For example, the emissive medium may be a Nd<3><+> doped fiber laser continuous with the probe.) The field changes within the tip are then evidenced as small variations in the complex reflectivity at one end of the cavity. It is well known that these variations can result in substantial changes in the optical output characteristics of the emissive medium. For example, they may result in large changes in the output power from the opposite end of a fiber laser, particularly when the laser is operated near threshold. This hybrid, near field, fiber laser probe (105) can also be used for optical data recording.