OCT - Optical Coherence Tomography 

OCT 

Optical Coherence Tomography 

OCT or Optical Coherence Tomography is a non-invasive, non-destructive method for sub-surface analysis. As one of the most fascination photonics applications, its benefits are widely recognized as a go-to technique for tissue imaging and is popular in ophthalmology where it has revolutionized eye diagnostics. In dermatology OCT it is the preferred technique to improve the resolution and depth range in skin imaging, which helps in diagnosing conditions like skin cancer.

However, OCT’s potential extends well beyond medical or healthcare applications. This versatile technology is increasingly applied across various industrial sectors, offering a powerful, non-invasive and non-contact solution for subsurface structure imaging needs in quality control, materials inspection, and process monitoring.

 

​OCT is gaining traction in the industrial sector for in-line and at-line inspection of multi-layered materials such as composites, polymers, ceramics, and opto-semiconductors.

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Light sources - ASE or SCG?

A significant number of OCT systems rely on ASE (Amplified Spontaneous Emission) light sources, such as SLED, which offers great efficiencies coupling into fiber compared to halogen or LED, but also present notable challenges: limited spectral range, which negatively impacts the axial resolution of OCT systems. To overcome this limitation, multiple ASEs are combined in a single package, which increases cost and complexity.

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Wideband lasers to the rescue 

Traditional wideband or supercontinuum lasers offer a wider spectrum, resulting in a high axial resolution in the OCT system, but typically come in a large form factor and require Class IV laser safety precautions which are not practical outside a lab and in a manufacturing environment. Both ASE and traditional supercontinuum lasers suffer from spectral noise which results in low contrast OCT scans.