Optical Feedback Height Control System Using Laser Diode Sensor for Near-Field Data Storage Applications

We demonstrated a laser diode position sensor for a near-field height control system. The feedback signal of the laser diode sensor that resulted from self-mixing interferometry was characterized and modeled by a simplified method. Due to the fine spatial resolution of the laser sensor, an active height control system with nanoscale position precision was designed and realized under a spinning disk for near-field applications.