Calibration Alignment Sensitivity in Corneal Terahertz Imaging

Area of Science:

• Biomedical Optics
• Terahertz Spectroscopy
• Corneal Imaging

Background:

• Corneal terahertz sensing is vital for diagnosing corneal dystrophies.
• Improving longitudinal modes coupling enhances sensing resolution.
• Calibration methods are crucial for accurate corneal property assessment.

Purpose of the Study:

• To investigate the impact of calibration sphere perturbations on corneal terahertz sensing.
• To quantify corneal characteristics using particle-swarm optimization under varying calibration scenarios.
• To determine optimal frequency bands for corneal feature assessment.

Main Methods:

• Utilized a steel sphere for calibrating corneal reflection measurements.
• Employed particle-swarm optimization to quantify corneal properties.
• Analyzed data across a frequency range of 100 GHz to 600 GHz and different signal-to-noise ratios (SNRs).
• Evaluated the effect of calibration sphere perturbations on estimation accuracy.

Main Results:

• Higher SNRs (40-60 dB) led to improved corneal property estimation.
• The WR-5.1 waveguide band (lower frequency) is most suitable for corneal feature assessment.
• Perturbations in the calibration sphere increased estimation errors by approximately 30% at 60 dB SNR.

Conclusions:

• Accurate calibration is essential for reliable corneal terahertz sensing.
• Perturbations in the calibration sphere significantly compromise diagnostic accuracy.
• The study provides insights into optimizing terahertz sensing for early corneal dystrophy detection.