Method to calibrate phase fluctuation in polarization-sensitive swept-source optical coherence tomography.

The research article presents a method to calibrate phase fluctuation in polarization-sensitive swept-source optical coherence tomography (PS-SS-OCT) using continuous polarization modulation, which was tested on an equine tendon sample.

Research Background

• This study focuses on the phenomenon known as phase fluctuation in a specific type of imaging method, specifically polarization-sensitive swept-source optical coherence tomography (PS-SS-OCT).
• The PS-SS-OCT method is used for capturing high-resolution images of fine structures within biological tissues. It is especially useful when needing a clear and detailed image of fibrous structures such as tendons and nerves.
• One of the challenges when using the PS-SS-OCT technique is the phase fluctuations that can interfere with the quality of the images. Phase fluctuations can distort and compromise the quality of images produced, making it difficult to visualize and analyze the intended structures.
• Hence, there is a need to create a method to calibrate or correct these phase fluctuations to ensure that the images produced by PS-SS-OCT are as clear and accurate as possible.

Introduced Calibration Method

• The researchers propose a phase fluctuation calibration method that uses continuous polarization modulation. This employs a low-voltage broadband polarization modulator driven by a synchronized sinusoidal burst waveform; different from the typical asynchronous waveform.
• The method also involves removing the global phases of the measured Jones matrices through matrix normalization.
• This approach allows the Jones matrices (which represent the state of polarization within the image) to be averaged. This helps remove any artifacts arising from the speckle noise of the signal in the sample, and it accomplishes this without the need to introduce auxiliary optical components into the sample arm.

Validation of the Method

• To validate this newly proposed method, the researchers applied it to measurements of an equine tendon sample using the PS-SS-OCT system.
• The equine tendon was used as a practical, biological example to demonstrate the application and effectiveness of this new calibration method.

Conclusion

• The article suggests that this phase fluctuation calibration method improves the utility and effectiveness of the PS-SS-OCT imaging technique.
• However, further research and testing might be required to ascertain the repeatability, practicality, and versatility of the method across different biological structures and under varying conditions.