650 GHz imaging as alignment verification for millimeter wave corneal reflectometry.

Area of Science:

• Biomedical Optics
• Terahertz Technology
• Ophthalmic Instrumentation

Background:

• Accurate alignment is critical for corneal reflectometry measurements.
• Millimeter-wave (MMW) frequencies offer unique properties for biological tissue analysis.
• Current alignment verification methods may lack precision or real-time feedback.

Purpose of the Study:

• To introduce a system concept for online alignment verification in MMW corneal reflectometry.
• To evaluate the system's capability to detect misalignments using reflectivity maps.
• To assess the achievable positional accuracy for MMW-based corneal imaging.

Main Methods:

• A system utilizing off-axis parabolic mirrors and a galvanometric mirror was designed and simulated.
• Magnitude-only reflectivity maps of the cornea were generated at 650 GHz.
• Images were compared to a template map for alignment verification.
• Geometric and physical optics simulations were performed.

Main Results:

• The demonstrator system detected sufficient misalignment in 23 out of 26 tested positions.
• Positional accuracy on the order of 0.5 mm was demonstrated.
• Sensitivity was attributed to beam distortion and walk-off effects at 0.462 mm wavelength.

Conclusions:

• The proposed system concept enables online alignment verification for MMW corneal reflectometry.
• The system demonstrates high sensitivity for detecting positional errors.
• This technology holds potential for enhancing precision in ophthalmic diagnostics.