Two dimensional scanning probe using off-axis magnetic force of single solenoid for 3D OCT imaging

We propose a single piece optical fiber-based two-dimensional scanning hand-held probe suitable for three-dimensional optical coherence tomography. The probe consists of only a single piece of optical fiber loaded with a bead of ferromagnetic material, which acts as a vibrating cantilever. The fiber cantilever is two dimensionally actuated with a single miniaturized solenoid. For effective beam focusing, a fiber lens is formed at the end of the fiber. The inductance and input current of the solenoid were 100 μH and 216 mA, respectively. The iron-bead on the fiber is located at the off-axis of solenoid for two-dimensional scanning. Then, by modulating the input current to the solenoid, it was possible to mechanically oscillate the fiber cantilever in an elliptically spiral pattern. With the proposed probe, 2-dimensional scanning could be experimentally achieved in a rate of 4 s/vortex across a scanning area of approximately 30 mm2, which could be controlled with the length of the fiber or/and the weight of the iron-bead. Three-dimensional tomographic image of a coin was successfully obtained with the spectral domain optical coherence tomography equipped with the proposed scanner. It is expected that the scheme of 2-dimentional scanning with a single actuator might be useful in various real-time imaging applications including OCT owing to the advantages of low cost, low power consumption, simple fabrication process and versatile design.