Common-Path Optical Coherence Tomography Using the Bessel Beam From Negative Axicon Optical Fiber Tip

In this work, a deep-seated negative axicon fiber tip (DSNA-FT) generating the Bessel-Gauss beam is proposed as an optical probe for a common-path optical coherence tomography (CPOCT) imaging. The axicon at the optical fiber tip is fabricated by etching the tip of a selective optical fiber in hydrofluoric acid under the influence of capillary action. The nondiffracting type quasi-Bessel beam from the DSNA-FT having a long depth of field, similar to 0.7 mm, is used for the CPOCT imaging of different type of samples, i.e., sticky tape, fish scale, and rice grain. The CPOCT with unique and simple optical fiber probe has achieved lateral resolution at least similar to 3.3 mu m maintained up to 3 mm working distance in air. This optical fiber tip is an excellent candidate for an endoscopic probe design.