Swept-source and spectral-domain optical coherence tomography—Educational setups for the undergraduate lab

Optical coherence tomography (OCT) has become increasingly important in fundamental research, medical diagnostics, material characterization, and industrial process monitoring. OCT measures the depth-dependent reflectivity of a sample with micrometer-scale resolution by analyzing the interference between light reflected from the sample and a reference arm. Despite its widespread application, OCT remains underrepresented in undergraduate curricula due to the complexity and cost of commercial systems. Our contribution presents educational implementations of the two most widely used OCT modalities: swept-source OCT and spectral-domain OCT. In our swept-source setup, a grating monochromator is used as a tunable light source, providing a clear and cost-effective realization of wavelength sweeping. For our spectral-domain setup, we developed a compact, self-built two-dimensional spectrometer enabling efficient spectral acquisition. Both systems are capable of producing three-dimensional representations of the internal sample structure. Designed with open architecture and minimal complexity, these setups prioritize visibility of core principles, making them well-suited for hands-on learning in undergraduate laboratory environments.