Full-field optical coherence microscopy with optimized ultrahigh spatial resolution

Abstract

Full-field optical coherence microscopy (FF-OCM) with isotropic spatial resolution of 0.5 μm (in water), at 700 nm center wavelength, is reported. A theoretical study of the FF-OCM axial response is carried out for maximizing the axial resolution of the system, considering the effect of optical dispersion. The lateral resolution is optimized by using water-immersion microscope objectives with a numerical aperture of 1.2. This ultrahigh-resolution FF-OCM system is applied to animal and human skin tissue imaging, revealing ultra-fine in-depth structures at the sub-cellular level.

Differences between time domain and Fourier domain optical coherence tomography in imaging tissues

“…For micron FDOCT and full field optical coherence tomography (FFOCT) (Dubois et al, 2002;Federici & Dubois, 2015;Gao, 2015;Zhu et al, 2015), the random properties of tissue should be taken into account. In this case, because the depth resolution is high, the light scattered from the correlated structures is measured.…”

Fractal analysis of en face tomographic images obtained with full field optical coherence tomography

“…In FFOCT imaging, at any moment only the tissue structures within a thin slice at a depth z in the focal region of the microscopic objective lens is imaged on the CCD surface because only the path length difference between the light reflected from the reference mirror and the light backscattered or reflected from this thin layer is within the very short temporal coherence length of the light source for system with low NA objective lenses or short longitudinal spatial coherence length for the system with large NA objective lenses and quasi‐monochromatic illumination . The thickness of the slice is usually defined by the temporal coherence length of the light along the depth direction and is less than 1 μm for light from a tungsten halogen lamp.…”

“…Full‐field optical coherence tomography (FFOCT) has the capability of generating micrometer or submicrometer resolution en face tomographic images of in vitro or in vivo tissues, making it possible to identify tissue neoplastic changes at early stages without really excising tissue or tissue specimens. Many research groups and Labs have tried to model the imaging properties, correctly interpreting the images and explore the possible applications of FFOCT in disease diagnosis, among which Dubois's Lab and Boccara's group have made significant contributions . For a review of the detailed development and applications of the technique, see Ref.…”

A compact high‐speed full‐field optical coherence microscope for high‐resolution in vivo skin imaging

“…Full‐field optical coherence microscopy (FF‐OCM), also referred to as full‐field optical coherence tomography (FF‐OCT), is an interferometry imaging technique derived from optical coherence microscopy (OCM), capable of en face tomographic imaging using full‐field illumination with a low‐coherence light source and full‐field detection with an area camera . As there is no depth of field constraint in en face imaging, high numerical aperture (NA) microscope objectives can be used in FF‐OCM to achieve high transverse resolution . High axial resolution can also be obtained in FF‐OCM by using a simple and inexpensive light source such as a halogen lamp or a broadband light‐emitting diode (LED) .…”

“…As there is no depth of field constraint in en face imaging, high numerical aperture (NA) microscope objectives can be used in FF‐OCM to achieve high transverse resolution . High axial resolution can also be obtained in FF‐OCM by using a simple and inexpensive light source such as a halogen lamp or a broadband light‐emitting diode (LED) . Cellular‐level imaging with FF‐OCM of biological tissues, ex vivo, has been widely reported .…”