Application of Bessel beam from deep seated negative axicon in optical coherence tomography of tissue structure

Abstract

In this work, a Bessel beam from a deep seated negative axicon (DSNA) tip is utilized as a probe in the common-path interferometric configuration for cross-section tissue imaging. The DSNA is fabricated at the one end of an optical fiber by capillary action using chemical etching in hydrofluoric acid (48% HF) which generates high-quality Bessel beam. It has a small central spot size and large depth of field which ensure the quality of Bessel beam. This Bessel beam is used to probe the sample. The beam reflected back from the sample and couples with the probe treated as a sample beam which interferes with the reference beam generated at the air-axicon interface and the interference spectrum is acquired at detector end. This spectrum is further processed to obtain an image of the sample. The lateral and axial resolution of the system is ~3.3μm and ~6.9μm respectively. The experiments have been conducted on the tissue of the chicken muscle-fiber and heart. This optical fiber probe can be an ideal choice for an endoscopic probe in future.