Category: Microscopy

Full-field optical coherence microscopy (FF-OCM) and optically sectioned fluorescence microscopy are two imaging techniques that are implemented here in a novel dual modality instrument. The two imaging modalities use a broad field illumination to acquire the entire field of view without raster scanning. Optical sectioning is achieved in both imaging modalities owing to the coherence gating property of light for FF-OCM, and a structured illumination setup for fluorescence microscopy. Complementary image data are provided by the dual modality instrument in the context of biological tissue screening. FF-OCM imaging modality shows the tissue microarchitecture, while fluorescence microscopy highlights specific tissue features ...

Optical microscope is a well known instrument with many applications in biomedical imaging and precise measurements. Nowadays a lot of modalities arose, which utilize combination of a microscope arrangement with other optical techniques, such as holography or low-coherence interferometry. The most important features of these modalities are related to the diffraction or coherence effects due to such combination, rather than to exact ways of lens aberrations correction. Therefore for analysis and understanding of these effects a theoretical model is necessary, which would be rigorous enough to take into account the diffraction and coherence effects and in the same time simple ...

In this paper we present a model of interference microscope image formation, which allows for analysis on unified basis of imaging different types of samples with different interference microscope modalities. The applicability of the proposed model to analysis of the coherence effects, arising in confocal and full-field interference microscopes, when imaging in depth of a layered sample, is shown. The effect of sample transversal structure on the coherence signal is also analyzed, showing that in this case the interference microscope can not be characterized by a single effective aperture and both illuminating and imaging apertures are important.

Aberrations in optical microscopy reduce image resolution and contrast, and can limit imaging depth when focusing into biological samples. Static correction of aberrations may be achieved through appropriate lens design, but this approach does not offer the flexibility of simultaneously correcting aberrations for all imaging depths, nor the adaptability to correct for sample-specific aberrations for high-quality tomographic optical imaging. Incorporation of adaptive optics (AO) methods have demonstrated considerable improvement in optical image contrast and resolution in noninterferometric microscopy techniques, as well as in optical coherence tomography. Here we present a method to correct aberrations in a tomogram rather than the ...

High frequency ultrasound imaging has evolved from classical acoustic microscopy to the multimodal ultrasound microscope which is available for quantitative C-mode, surface acoustic impedance mode and 3D-mode imaging. The evolution has realized both quantitative parametric imaging and easier observation. Quantitative C-mode representing two-dimensional distribution of attenuation or sound speed is realized by frequency-domain analysis of a single pulse by a high speed digitizer. Because the square of sound speed is proportional to the tissue elasticity, sound speed imaging provides biomechanical information of the tissues which is especially important in cardiology and orthopedic surgery. The data also help understanding clinical echo ...

Full-field optical coherence tomography (FF-OCT) is a recent optical imaging technology based on low-coherence interference microscopy for imaging of semi-transparent samples with ~1 µm spatial resolution. FF-OCT produces en-face tomographic images obtained by arithmetic combination of interferometric images acquired by an array camera. In this paper, we demonstrate a unique multimodal FF-OCT system, capable of measuring simultaneously the intensity, the power spectrum and the phase-retardation of light backscattered by the sample being imaged. Compared to conventional FF-OCT, this multimodal system provides enhanced imaging contrasts at the price of a moderate increase in experimental complexity and cost.

Terahertz (THz) interferometric synthetic aperture tomography (TISAT) for confocal imaging within extended objects is demonstrated by combining attributes of synthetic aperture radar and optical coherence tomography. Algorithms recently devised for interferometric synthetic aperture microscopy are adapted to account for the diffraction—and defocusing-induced spatially varying THz beam width characteristic of narrow depth of focus, high-resolution confocal imaging. A frequency-swept two-dimensional TISAT confocal imaging instrument rapidly achieves in-focus, diffraction-limited resolution over a depth 12 times larger than the instrument’s depth of focus in a manner that may be easily extended to three dimensions and greater depths.

Join SP Scientific's next FREE LyoLearn webinar on March 27, 2012 -- Physical Sciences Inc. (PSI) in collaboration with the University of Connecticut has developed a new Optical Coherence Tomography based Freeze Drying Microscopy (OCT-FDM) technique that results in more accurate collapse temperature determinations representative of what is observed during production scale drying.

According to a first aspect, the invention relates to a multimodal optical sectioning microscope (200, 400, 600) for full-field imaging of a volumic and scattering sample comprising: - a full-field OCT system for providing an image of a first section in depth of the sample comprising an illumination sub-system (201, 401, 601) and a full-field imaging interferometer with a detection sub system (208, 408, 608) and an optical conjugation device for optically conjugating the sample and said detection sub system, wherein said optical conjugation device comprises a microscope objective (203, 403, 603), - a supplementary full-field optical sectioning imaging system for providing ...

The present invention relates to a full-field optical coherence tomography system (300) for imaging an object (319), comprising a light source (301), a first interferometric device having means for splitting an input light beam and comprising at least a reflecting surface (307), a second interferometric device having means for splitting the spectrally modulated output beam and comprising at least a reflecting surface, a multichannel acquisition device (321), the system (300) being characterized in that at least one of the interferometric devices includes at least a focusing optical element arranged to focus at least one of the input beams or at ...

We present a polarization Linnik interference microscope with a nematic liquid-crystal (NLC) phase shifter for full-field optical coherence tomography of high-quality images. The rotating half-wave plate in conventional achromatic phase shifters was replaced by three liquid-crystal (LC) half-wave plates for implementing three-step phase-shifting interferometry. Thus, the NLC device generates phase shifts quickly and has no vibrations. In addition, the phase shift can be set to an arbitrary value between 0 and 2π by altering the azimuth angles of the LC cells. A tomographic image is retrieved from three sequential phase-shifted interferograms by using a three-step algorithm. The experimental results confirm ...

Cutaneous aging is a complicated biological process affecting different constituents of skin, which can be divided into two types: the chronological aging and the photo-aging. The two cutaneous aging processes often co-exist accompanying with each other. The effects are often overlapped including changes in epithelium and dermis. The degeneration of collagen is a major factor in dermal alteration with aging. In this study, multiphoton microscopy (MPM) with its high resolution imaging and optical coherence tomography (OCT) with its depth resolved imaging were used to study the anti-aging dermatology in vivo. It was attempted to make the optical parameter and texture ...

Optical Coherence Tomography (OCT) is an efficient technique for in-depth optical biopsy of biological tissues, relying on interferometric selection of ballistic photons. Full-Field Optical Coherence Tomography (FF-OCT) is an alternative approach to Fourier-domain OCT (spectral or swept-source), allowing parallel acquisition of en-face optical sections. Using medium numerical aperture objective, it is possible to reach an isotropic resolution of about 1x1x1 m. After stitching a grid of acquired images, FF-OCT gives access to the architecture of the tissue, for both macroscopic and microscopic structures, in a non-invasive process, which makes the technique particularly suitable for applications in pathology. Here we report ...

We developed optical coherence photoacoustic microscopy (OC-PAM) to demonstrate that the functions of optical coherence tomography (OCT) and photoacoustic microscopy (PAM) can be achieved simultaneously by using a single illuminating light source. We used a pulsed broadband laser centered at 580 nm and detected the absorbed photons through photoacoustic detection and the back-scattered photons with an interferometer. In OC-PAM, each laser pulse generates both one OCT A-line and one PAM A-line simultaneously; as a result, the two imaging modalities are intrinsically co-registered in the lateral directions. In vivo images of the mouse ear were acquired to demonstrate the capabilities of ...

We present a benchmark pilot study in which high-resolution Full-Field Optical Coherence Tomography (FF-OCT) is used to image human breast tissue and is evaluated to assess its ability to aid the pathologist's management of intra-operative diagnoses. Our aim included evaluating the safety of FF-OCT on human tissue and determining the concordance between the images obtained with routinely prepared histopathological material. The compact device used for this study provides a 2 {\mu}m-lateral and a 1 {\mu}m-axial resolution, and is able to scan a 1.5cm^2 specimen in about 7 minutes. 75 breast specimens obtained from 22 patients ...