- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
low-coherent optical diffraction tomography by angle-scanning illumination
摘要： Temporally low-coherent optical diffraction tomography (ODT) is proposed and demonstrated based on angle-scanning Mach–Zehnder interferometry. Using a digital micromirror device based on diffractive tilting, the full-field interference of incoherent light is successfully maintained during every angle scanning sequences. Further, current ODT reconstruction principles for temporally incoherent illuminations are thoroughly reviewed and developed. Several limitations of incoherent illumination are also discussed, such as the nondispersive assumption, optical sectioning capacity, and illumination angle limitation. Using the proposed setup and reconstruction algorithms, low-coherent ODT imaging of plastic microspheres, human red blood cells, and rat pheochromocytoma cells is experimentally demonstrated.
关键词： quantitative phase imaging,low-coherent,optical diffraction tomography,coherent noise
更新于2025-09-23 15:23:52
-
Double-Track Waveguides inside Calcium Fluoride Crystals
摘要： Calcium Fluoride (CaF2) was selected owing to its cubic symmetry and excellent luminescence properties as a crystal of interest, and ultrafast laser inscription of in-bulk double-track waveguides was realized. The guiding properties of these waveguides in relation to the writing energy of the femtosecond pulse are presented. The modified double-track waveguides have been studied by systematic developments of beam propagation experiments and numerical simulations. Furthermore, an adapted model and concepts were engaged for the quantitative and qualitative characterization of the waveguides, particularly for the transmission loss measurements and the three-dimensional refractive index mappings of the modified zones. Additionally, polarization-dependent guiding was investigated.
关键词： Calcium Fluoride,quantitative phase imaging,waveguides,femtosecond lasers,cubic crystal,micro-processing,double-track,photonic device,direct laser writing (DLW),refractive index change
更新于2025-09-16 10:30:52
-
[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Quantitative Phase Microscopy with Molecular Vibrational Sensitivity
摘要： Quantitative phase imaging (QPI) has become a valuable tool for studying optically transparent samples such as biological cells and tissues. It yields the sample-specific optical path-length delay at each spatial point of the field of view with a nanometer resolution, enabling high-contrast and objective analysis. The major advantage of QPI is its wide-field, label-free measurement capability of the transparent morphology. This allows for high-speed imaging limited by the image sensor’s frame rate while reducing optical and/or chemical damages to the sample which are troublesome in other imaging techniques such as fluorescence and Raman imaging. To date, QPI has been used for pathology diagnosis, phenotyping of live cancer cells, non-destructive measurement of cellular volume and dry-mass, study of cellular membrane dynamics, to just name a few. However, QPI lacks chemical sensitivity which limits its application to morphology-based diagnosis. Here, we report on our wide-field label-free molecular-vibrational (MV) microscopy method realized in the framework of QPI utilizing mid-infrared (MIR) photothermal effect. We measure local changes in the optical phase delay occurring upon absorption of the MIR light in the vicinity of the MV-resonant molecules, which is called photothermal effect, by means of QPI. This imaging scheme yields high-molecular-detection sensitivity based on MV-resonant MIR absorption having ~8 orders of magnitude larger cross-section compared to Raman scattering. Meanwhile, it also maintains the visible-light spatial resolution, high temporal resolution limited by the image sensor’s frame rate, and low photodamage to the sample with the wide-field, low-fluence optical illumination. Notably, our wide-field, parallelized detection scheme could even surpass the imaging speed of conventional label-free imaging methods such as coherent Raman imaging by an order of magnitude, as they typically employ a point-scanning mechanism for image synthesis. Our MV-sensitive QPI (MV-QPI) could offer new insights for optically-transparent complex dynamics by enabling high-speed, label-free cross-correlative analysis based on the quantitative morphology and the MV-spectroscopic chemical contrasts.
关键词： molecular-vibrational microscopy,Quantitative phase imaging,chemical sensitivity,label-free imaging,mid-infrared photothermal effect
更新于2025-09-12 10:27:22
-
Wavefront reconstruction of vortex beams via a simplified transport of intensity equation and its symmetry based error reduction
摘要： We present an unexplored non-interferometric approach for wavefront measurement of vortex beams based on the transport of intensity equation. By exploiting the symmetries of vortexes we are able to simplify the transport of intensity equation to a reduced expression not reported before in the context of phase imaging. This reduced model can be solved to measure the phase profile of vortexes via one-dimensional operations only without the complexities pertaining the regular transport of intensity equation. We also use the axial symmetry exhibited by the intensity profile of vortexes to build a noise filtering scheme exclusive to circularly symmetric images and thus address electronic noise in digital imaging systems. We present a series of numerical experiments both to clarify how to apply our proposal step by step and to prove its overall functionality.
关键词： optics,free-space,orbital angular momentum,noisy data,axial symmetry,quantitative phase imaging,non-interferometric techniques,optical vortex
更新于2025-09-09 09:28:46
-
Label-Free Identification of Lymphocyte Subtypes Using Three-Dimensional Quantitative Phase Imaging and Machine Learning
摘要： We describe here a protocol for the label-free identification of lymphocyte subtypes using quantitative phase imaging and machine learning. Identification of lymphocyte subtypes is important for the study of immunology as well as diagnosis and treatment of various diseases. Currently, standard methods for classifying lymphocyte types rely on labeling specific membrane proteins via antigen-antibody reactions. However, these labeling techniques carry the potential risks of altering cellular functions. The protocol described here overcomes these challenges by exploiting intrinsic optical contrasts measured by 3D quantitative phase imaging and a machine learning algorithm. Measurement of 3D refractive index (RI) tomograms of lymphocytes provides quantitative information about 3D morphology and phenotypes of individual cells. The biophysical parameters extracted from the measured 3D RI tomograms are then quantitatively analyzed with a machine learning algorithm, enabling label-free identification of lymphocyte types at a single-cell level. We measure the 3D RI tomograms of B, CD4+ T, and CD8+ T lymphocytes and identified their cell types with over 80% accuracy. In this protocol, we describe the detailed steps for lymphocyte isolation, 3D quantitative phase imaging, and machine learning for identifying lymphocyte types.
关键词： lymphocyte identification,machine learning,holotomography,immune cell,immunology,Immunology and Infection,Quantitative phase imaging,optical diffraction tomography,holographic microscopy,label-free imaging
更新于2025-09-04 15:30:14
-
[IEEE 2018 20th International Conference on Transparent Optical Networks (ICTON) - Bucharest (2018.7.1-2018.7.5)] 2018 20th International Conference on Transparent Optical Networks (ICTON) - Recent Advances in Digital Holographic Microscopy
摘要： In digital holographic microscopy (DHM) a hologram is captured in the image space provided by a microscope. The transfer of the phase and amplitude structure in the original sample to the hologram is in fact strongly affected by the use of the imaging microscope. A big research effort has been devoted to correct these distortions both by numerical and optical compensation. In this contribution, we present several proposals to improve the performance of classical DHM architectures by an a priori approach to compensate physically these perturbations. Experimental results are also presented to validate the proposed techniques.
关键词： holography,digital holographic microscopy,quantitative phase imaging
更新于2025-09-04 15:30:14