Simple device and reproducible approach for producing high efficiency optical fiber tips for a scanning near-field optical microscope

A heating–pulling device is established for producing the optical fiber probe used in scanning near-field optical microscopy. A ${\mathrm{CO}}_{\mathrm{2}}$ laser, the power of which can be adjusted continuously between 0 and 10 W, is used as the heating source. Pulling is done by two identical motors. On the basis of the device, a novel approach different from the conventional heating–pulling method is developed, which eliminates the need for a computer, reflective mirror, and varied force during tip formation. Thus it is simple and easy to use. The cost is reduced greatly. Tips with parabolic taper, short taper region, and a diameter of 65 nm, which are optimal conditions for high transmission efficiency, are obtained.