Imaging systems based on optical interferometry are widely used because they are non-invasive, provide high resolution, and have a long working distance. However, they are often slow limiting industrial applications.
Associate Prof. Tatsutoshi Shioda and his team have overcome the speed challenge by incorporating a supercontinuum laser and a spatial phase modulator (SPM) as a critical component of the reference part of the interferometers used for tomography and profilometry. Hereby, the line-shape interference fringes are generated directly on a CCD creating a single-shot system that can run at very high speed.
Additionally, by rotating the SPM to switch the diffraction light for the interferometer, the magnification of the tomogram image can be changed while keeping the same resolution – i.e. optical zoom. A World’s first for this kind of system.
“NKT Photonics’ Supercontinuum light is really the powerful source for the broadband interferometry based tomography because of high optical power, super-wide bandwidth, and flexible optical filter. We are using both SuperK EXTREME and COMPACT (for more than 2 years without any troubles) for high-speed, high-resolution, and non-destructive profilometry and tomography, which is very important for an in-line product inspection processes in the automobile industry.”
Associate Prof. Tatsutoshi Shioda, Advanced Photonics & Sensing Laboratory, Saitama University
- Tuan Quoc Banh, Takaya Kosakai, Ryoma Onita, Tatsutoshi Shioda, “Interference fringe order distinction for single-shot tomography based on two wavelengths comb interferometry”, in Optics and photonics of Japan 2014, paper 7aD5.
- Tuan Quoc Banh and Tatsutoshi Shioda, “Control the optical magnification of a zooming tomography and profilometry with a spatial phase modulator installed interferometer,” in Advanced Photonics 2015, OSA Technical Digest (online) (Optical Society of America, 2015), paper SeT4C.5.