Multifocal spectral-domain optical coherence tomography based on Bessel beam for extended imaging depth

Area of Science:

• Biomedical Imaging
• Optical Engineering
• Metrology

Background:

• Optical Coherence Tomography (OCT) is vital for biomedical imaging.
• A key limitation of OCT is the trade-off between lateral resolution and depth of field (DOF).
• Extending imaging depth without sacrificing resolution is crucial for practical OCT applications.

Purpose of the Study:

• To propose and demonstrate a novel multifocal Bessel beam spectral-domain optical coherence tomography (MBSDOCT) technique.
• To overcome the inherent resolution-DOF trade-off in conventional OCT.
• To achieve extended imaging depth with maintained lateral resolution and high signal-to-noise ratio.

Main Methods:

• Development of a multifocal Bessel beam spectral-domain optical coherence tomography (MBSDOCT) system.
• Utilizing an axicon lens to generate multifocal Bessel beams.
• Theoretical analysis and experimental validation of the MBSDOCT technique.

Main Results:

• Theoretical DOF of approximately 6 mm with a lateral resolution of approximately 13 μm was achieved using a three-focal MBSDOCT.
• Experimental imaging of orange acinar cells demonstrated a measured DOF of approximately 4 mm.
• A sensitivity penalty of approximately 18.1 dB was observed relative to Gaussian beam OCT, using a 9-mW light source.

Conclusions:

• The proposed MBSDOCT technique effectively extends the depth of field in OCT.
• MBSDOCT offers a promising solution for enhanced biomedical imaging applications requiring greater penetration depth.
• Further optimization may reduce the sensitivity penalty for broader clinical adoption.