Phase sensitive spectral domain optical coherence tomography for latent fingerprint detection

We present a joint spectral and depth domain spectral domain phase microscopy for high-sensitive and high-dynamic-range quantitative phase imaging, where phase information retrieved in spectral domain is used to overcome the limitation of 2π ambiguity and phase information in depth domain is used to achieve a high phase sensitivity. By theoretical derivation and simulation, the sensitivity advantage of phase information in depth domain over phase information in spectral domain is investigated. The theoretical derivation of joint spectral and depth domain spectral domain phase microscopy is presented in detail. The performance of the proposed joint spectral and depth domain spectral domain phase microscopy is illustrated by phase imaging of a coverslip and a resolution target.

Joint spectral and depth domain spectral domain phase microscopy

Yan¹,

Zhihua²,

Wang³

et al. 2013

Line-field parallel spectral domain optical coherence tomography and its application in defect inspection

Zhao¹,

Chen²,

Ding³

et al. 2014

For the needs of online nondestructive testing method in glass industry, we have presented a large-range line-field parallel spectral domain optical coherence tomography system. Based on fast area scan CMOS camera, the whole cross-sectional image can be acquired by a single shot. Depth-resolved image at different lateral positions can be acquired simultaneously, without the lateral scanning mechanism. The axial resolution is 17.9 μm, the lateral resolutions in parallel direction and scanning direction are 55.7 μm and 24.8 μm, respectively. The system measurement range is 32 mm in lateral direction and 6 mm in axial direction. At 1 mm axial position, the system sensitivity can reach 62 dB at a rate of 128 000 A-scan/s. By using the present system, application in glass defect inspection has been investigated.

Ultrahigh-resolution optical coherence tomography and its application in inspection of industrial materials

Tang¹,

Chen²,

Chen³

et al. 2015

Since many industrial materials have micro or submicro structures on the surface or subsurface, utrahigh-resolution is required in the inspection of these materials. Ultrahigh-resolution optical coherence tomography uses broadband light sources to achieve axial image resolutions on the scale of a few microns. We have been investigating an ultrahigh-resolution spectral-domain optical coherence tomography (SD-OCT) system using supercontinuum sources (SC) in free space. The effective SC spectrum has a full width at half maximum of 230 nm centered around 665 nm, and the imaging setup has an ultrahigh axial resolution of 0.9 μm in air, and a lateral resolution of 3.9 μm, with the system measurement range being 0.6 mm in axial direction. At a 50 μm axial position, the sensitivity can be 63 dB with 28600 axial scans per second at 2048 pixels per axial scan. Images of polystyrene microspheres solution with an average diameter of 5 μm and different sizes of industrial abrasive papers are presented to illustrate the performance of the system.