The Hybrid Fourier Domain OCT instrument uses a supercontinuum laser source to provide the illumination for both systems. ​ The SWIR portion of the spectrum is split off for use as the OCT broad band laser source. The OCT system consists of a free-space Michaelson interferometer and InGaAs detector-based spectrometer. This enables OCT operation at a central wavelength of 1350 nm with an approximate spectral bandwidth of 200 nm, providing an axial (depth) resolution of 5 µm in air (3.3 µm in paint n=1.5). Rapid collection of 3D OCT data sets are constructed by scanning the laser spot via a pair of galvometer scanning mirrors. The typical lateral resolution in the plane of the object's surface is 10 µm, and the field of view is 5 mm x 5 mm with a working distance of 40 mm. It can collect an image cube consisting of 500 x 500 depth profiles in ~10 seconds. The typical laser intensity at the object surface is ~1.5 mW. The OCT probe can be mounted on a motorised XYZ translation stage to take adjacent image cubes to mosaic a larger area.​ The visible/ near infrared portion of the spectrum is coupled into a variable tuneable filter to provide filtered illumination spanning from 415 nm to 845 nm with a tuneable spectral bandwidth between 10 and 100 nm. The filtered output is then coupled to a fibreoptic ring light, to provide a uniform illumination field incident on the object at 20° from the optical axis (usually perpendicular to the objects surface). Spectral images can be constructed by sequentially changing the spectral band of the tuneable filter and collecting images with a monochrome CMOS camera through the same objective lens as the OCT. A typical 44 band spectral image at a 10 nm bandwidth is collected with approximately 1 minute and covers a 5mm imaging circle at a spatial resolution of 5 µm.

Image/Multi band image
Dataset/2D
Dataset/3D

Noncontact (no physical contact)
Nondestructive (no permanent damage or alteration)
Noninvasive (no physical alteration)

ISAAC in-house developed instrument

4 x 4 mm