Dual-side view optical coherence tomography for thickness measurement on opaque materials

Area of Science:

• Optical imaging
• Metrology
• Materials science

Background:

• Optical coherence tomography (OCT) is an optical interferometric technique effective for imaging layered structures and measuring thickness.
• Traditional OCT is limited to non-opaque materials due to light attenuation, restricting its application in thickness measurement.
• Measuring the thickness of opaque materials presents a significant challenge in various scientific and industrial fields.

Purpose of the Study:

• To develop a novel dual-side view OCT (DSV-OCT) system capable of measuring the thickness of opaque materials.
• To overcome the limitations of conventional OCT regarding imaging depth and material opacity for thickness measurements.
• To demonstrate the accuracy and feasibility of the DSV-OCT technique for opaque material thickness assessment.

Main Methods:

• A dual-side view OCT (DSV-OCT) system was developed on a swept-source OCT platform.
• Two symmetrical sampling arms were engineered to achieve simultaneous imaging of both material surfaces.
• Surface contours of both sides were acquired in a single C-scan, enabling thickness calculation.

Main Results:

• The developed DSV-OCT system successfully imaged both surfaces of opaque materials simultaneously.
• Thickness of opaque materials was calculated from the acquired dual surface contours.
• The DSV-OCT technique demonstrated a thickness measurement accuracy of approximately 3 µm.

Conclusions:

• The novel DSV-OCT system effectively measures the thickness of opaque materials, expanding OCT applications.
• Simultaneous dual-side imaging overcomes light attenuation limitations inherent in conventional OCT for opaque samples.
• The high accuracy achieved by DSV-OCT makes it a valuable tool for precise thickness metrology in opaque materials.