Optical Coherence Tomography (OCT) was first introduced and commercialized in the 90’ties and from a commercialization perspective it has developed in 3 technology generation.
First generation was time-domain OCT (TD-OCT) which was slow due to need for sweeping the mechanical delay line. This makes it useful for A-scan or OCDR imaging, such as for biometers, but not for tomography where the slow acquisition rate impedes sufficient resolution to be achieved on the B-scan.
Second generation was Spectral-Domain OCT (SD-OCT) which was spurred by the development of fast and cost-efficient spectrometers enabling Fourier-Domain OCT (FD-OCT) at center wavelength in the range of around 8-900nm where silicon photodetectors have good sensitivity. For longer wavelength InGaAs photodetectors was available, but it is not until recently prompted by the adoption in fiber communication that they have begun to be competitive. In FD-OCT multiple wavelengths are detected at the same time which improves greatly the SNR and speed why FD-OCT has been commercially successful for B-scan and even C-scan imaging.
Third generation was Swept-Source (SS-OCT) based on Swept Source lasers, only requiring a single detector, that can sample much faster than CMOS high-resolution spectrometers, enabling >10x faster imaging rate opening for larger field of view and velocity information. Swept Source lasers do not have the inherent trade-off from the spectrometer that limits the linewidth and thus SS-OCT enables >10x larger imaging depth. Recently the rise of the Photonics Integrated Circuit (PIC) industry has also shown the path to further miniaturization.
More variations of Swept Sources are under development such as Fuld-Field OCT (FF-OCT), and Adaptive Optics OCT (AO). OCTLIGHT is following the vibrant research community closely to stay at the forefront of technology development and adoption.