Self-aligned microlens fabricated on the sidewall of 45°-angled optical fiber for NSOM illumination system

A miniaturized illumination system, which consists of a waveguide with an integrated 45° TIR (total internal reflection) mirror and a microlens for a compact high-capacity optical data storage, is proposed and fabricated. The micro illumination system can be realized by changing the incident lateral optical path into the vertical direction with a horizontal placement of 45°-angled optical fiber. The refractive index of the optical fiber is 1.45 and the critical incident angle of TIR is 43.4° at the fiber-air interface. Therefore, the 45°-angled end-face of optical fiber satisfies the TIR condition with no metal coating for mirror reflection.