OSeeT

• OCT is based on (coherence gated) interferometry.
• Light is split in reference and probe path.
• Optics of the sample arm focus light and define lateral (=surface) resolution in focus.
• Interference of light reflected back from both paths.
• Spectrometer (grating, high-speed CMOS sensor).
• Depth-information is generated from interference by non- linear Fourier-transformation (nu-FFT).
• Depth scan measurement rate: 130 – 250 kHz (depending on OSeeT system version).
• Direct thickness measurement (optical path length).
• Each interferogram -> one depth reading (“A-scan”, 1D). A-scan rate: 130kHz-250kHz max.
• Multiple A-scans -> cross-sectional image (“B-scan”, 2D). Requires moving of objects or a scanning sensor beam.