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We present a space-angle dual multiplexing holographic recording system for realizing single-exposure multi-wavelength optical diffraction tomographic (ODT) imaging. This system is achieved by combining the principle of single-exposure multi-wavelength holographic imaging technique based on angle-division multiplexing with the principle of single-exposure ODT imaging technique based on microlens array multi-angle illuminations and space-division multiplexing. Compared with the existing multi-wavelength ODT imaging methods, it enables the holographic recording of all the diffraction tomography information of a measured specimen at multiple illumination wavelengths in a single camera exposure without any scan mechanism. Using our proposed data processing method, the multi-wavelength three-dimensional (3D) refractive index tomograms of a specimen can be eventually reconstructed from single recorded multiplexing hologram. Experimental results of a static polystyrene bead and a living C. elegans worm demonstrate the feasibility of this system.
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We present a simple system for realizing single-shot ultrafast sequential imaging based on spatial multiplexing in-line holography. In this system, we propose to combine a specially designed mini-reflector delay-line array with digital in-line holography. The former including a group of adjustable mini-reflectors can easily generate an array of probe sub-pulses that can be controlled independently in the propagation direction and time delays. The object beams formed by the different sub-pulses will propagate and fall on different recording regions of the image sensor to generate a single-shot spatial-multiplexing in-line hologram. The geometry of the digital in-line holography can simplify the complexity of the system and enable complex amplitude imaging. In addition, the time resolution of this system is limited only by the pulse duration, which allows this system to study the dynamic processes with the femtosecond order. In an experiment about the laser-induced air plasma, our proposed system achieves nine frames sequential holographic images with the frame rate of 7.5 trillion frames per second (Tfps).
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We present a new, to the best of our knowledge, type of off-axis digital holographic imaging method with a long field of view (FOV). In the method, the pre-magnification recording geometry is realized by a cylindrical lens (CL) or cylindrical beam instead of a conventional objective or spherical beam in traditional off-axis digital holography (DH). At the same time, the reference beam is replaced by a divergent cylindrical beam. Theoretical analysis and experiments have justified that, in off-axis DHs, the adoption of the cylindrical beams can realize a one-dimensional pre-magnification of the object beam only in the off-axis direction to satisfy the bandwidth constraint, and at the same time the FOV of the reconstructed image in the orthogonal direction can remain unaffected. In comparison with existing off-axis DHs, this cylindrical wave-based DH (CWDH) method has a distinct advantage in expanding the FOV of the reconstructed image. The FOV feature of the CWDH makes it especially suitable for applications that require a long FOV such as imaging samples in microfluidic channels.
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Birefringence is an important optical property of anisotropic materials arising from anisotropies of tissue microstructures. Birefringence parameters have been found to be important to understand optical anisotropic architecture of many materials and polarization imaging has been applied in many researches in the field of biology and medicine. Here, we propose a scheme to miniaturize a double-channel polarization holographic interferometer optics to create a polarization holographic microscope slide (P-HMS) suitable for integrating with microfluidic lab-on-a-chip (LoC) systems. Based on the P-HMS combined with a simple reconstruction algorithm described in the paper, we can not only simultaneously realize holographic imaging of two orthogonal polarization components of dynamic samples in a microfluidic channel but also quantitative measurement of 2D birefringence information, both including the birefringence phase retardation and optic-axis orientation. This chip interferometer allows for off-axis double-channel polarization digital holographic recording using only a single illumination beam without need of any beam splitter or mirror. Its quasi-common path configuration and self-aligned design also make it tolerant to vibrations and misalignment. This work about the P-HMS could play a positive role in promoting the application of birefringence imaging in microfluidic LoC technology.
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A compact system for single-shot sequential holographic imaging (SSSHI) with high temporal resolution and a large field of view is proposed. In this system, a specially designed sequence pulse train generator with a group of diffractive gratings inserted is adopted to simultaneously generate the probe pulse train and the reference pulse train required for recording a single-shot spatial frequency division multiplexing hologram. The system successfully overcomes the walk-off effect of the ultrashort pulse laser in SSSHI and, hence, effectively avoids the influence of the short coherence of ultrashort pulses on the spatial resolution (or field of view) of SSSHI; the complexity of the system and the difficulty in the precise synchronous alignment of the probe and the reference pulses also can be greatly reduced. An experimental setup of the system was constructed, and a SSSHI of dynamical air plasmas induced by a femtosecond pulse laser is successfully realized.
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A method for realizing 2D single-shot measurements of birefringence parameters (including both retardation and optic axis orientation) of anisotropic materials using a simple recording setup and an efficient processing algorithm is proposed. The recording setup can be built simply by inserting a circular polarizer and a polarization beam splitter, respectively, in the object path and reference path of a conventional off-axis holographic imaging system, with no need for other adjustments. An algorithm for quantitatively retrieving the birefringence parameters from one single-shot hologram is proposed and demonstrated, in which a new quantity describing the birefringence, called complex birefringence parameter, is introduced, and a set of formulas used to extract the birefringence parameters is derived. Some experimental results are given for demonstrating the feasibility of the method that reveal that the method may provide another effective approach for investigating the birefringence properties of dynamic anisotropic materials, especially the birefringence induced by ultrafast pulse lasers.
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We propose a quantitative phase imaging system with exact slightly-off-axis configuration and suitable for objects both smaller and larger than the size of the effective recording region of the image sensors. In this system, the object is illuminated by a convergent spherical beam and a specially designed aperture filter is placed on the spatial frequency plane of the object wave; at the same time, a point source emitting from the edge of the aperture is taken as the reference beam, so that the optimal frequency condition for reconstruction of slightly-off-axis digital holograms can be always guaranteed for both large and small objects as well as different magnification (or the field of view) configurations. At the same time, a 1x2 single-mode optical fiber splitter is used for generating the reference and the illumination beams. Benefited from such fiber-based slightly-off-axis design, the proposed system provides a low-cost way to convert a regular microscope into a slightly-off-axis holographic one for microbiological specimens with a high spatial resolution.
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This study aimed to compare the efficacy and safety of rituximab (RTX) plus recombinant human thrombopoietin (rhTPO) with RTX alone in patients with immune thrombocytopenia (ITP) who had failed to respond to corticosteroids or relapsed. Recruited patients were randomized at a ratio of 2:1 into 2 groups: the combination group (RTX + rhTPO, n = 77) and the monotherapy group (RTX, n = 38). Overall response was achieved in 79.2% of patients in the combination group vs 71.1% in the monotherapy group (P = .36), and the complete response (CR) rate was 45.4% in the combination group compared with 23.7% in the monotherapy group (P = .026). The combination group had significantly shorter time to response (TTR; median and range, 7 and 4-28 days) compared with the monotherapy group (28 and 4-90 days) (P < .01). There was no difference between these 2 groups in terms of the long-term response (P = .12). Our findings demonstrated that the combination of RTX and rhTPO significantly increased the CR rate and shortened TTR compared with RTX monotherapy in the treatment of corticosteroid-resistant or relapsed ITP but failed to show a beneficial effect on the long-lasting response. This study is registered at www.clinicaltrials.gov as #NCT01525836.
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Anticorpos Monoclonais Murinos/administração & dosagem , Púrpura Trombocitopênica Idiopática/tratamento farmacológico , Púrpura Trombocitopênica Idiopática/terapia , Trombopoetina/administração & dosagem , Adolescente , Corticosteroides/uso terapêutico , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Monoclonais Murinos/efeitos adversos , Autoanticorpos/sangue , Criança , Terapia Combinada , Resistência a Medicamentos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Contagem de Plaquetas , Púrpura Trombocitopênica Idiopática/sangue , Proteínas Recombinantes/administração & dosagem , Proteínas Recombinantes/efeitos adversos , Recidiva , Rituximab , Trombopoetina/efeitos adversos , Resultado do Tratamento , Adulto JovemRESUMO
We report a fiber-based lensless holographic imaging system to realize a single-shot measurement of two dimensional (2-D) Jones matrix parameters of polarization-sensitive materials. In this system, a multi-source lensless off-axis Fresnel holographic recording geometry is adopted, and two optical fiber splitters are used to generate the multiple reference and illumination beams required for recording a four-channel angular-multiplexing polarization hologram (AMPH). Using this system and the method described in this paper, spatially resolved Jones matrix parameters of a polarization-sensitive material can be retrieved from one single-shot AMPH. We demonstrate the feasibility of the method by extracting a 2-D Jones matrix of a composite polarizer. Applications of the method to measure the Jones matrix maps of a stressed polymethyl methacrylate sample and a mica fragment are also presented. Benefit from the fiber-based and lensless off-axis holographic design, the system possesses a quite compact configuration, which provides a feasible approach for development of an integrated and portable system to measure Jones matrix parameters of polarization-sensitive materials.
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A time-resolved holographic polarization microscopy, based on angular multiplexing holographic technique, is proposed for imaging ultrafast phenomena in polarization-sensitive transparent materials. This method can retrieve and image the complex amplitude distributions of two orthogonal polarization components of two sequential vector wavefronts with ultrashort time interval by a single short recording. Some experimental results for imaging the pulse laser induced ultrafast events based on the method are given. It is demonstrated that this technique may provide a potential tool for characterizing ultrafast processes in polarization-sensitive materials, especially in the non-reproducible experiment conditions.
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We propose a double-channel angular-multiplexing polarization holographic imaging system with common-path and off-axis configurations. In the system, its input plane is spatially divided into three windows: an object window and two reference windows, and two orthogonal linear polarizers are attached, respectively, on the two reference windows; a two-dimensional cross grating is inserted between the input and output planes of the system. Thus the object beam passing through the object window and the two orthogonal polarized reference beams passing through the two reference windows can overlap each other at the output plane of the system and form a double-channel angular-multiplexing polarization hologram (DC-AM-PH). Using this system, the complex amplitude distributions of two orthogonal polarized components from an object can be recorded and reconstructed by one single-shot DC-AM-PH at the same time. Theoretical analysis and experimental results demonstrated that the system can be used to measure the Jones matrix parameters of polarization-sensitive or birefringent materials.
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A wavefront sensing method based on a spatial light modulator (SLM) and an incremental binary random sampling (IBRS) algorithm is proposed. In this method, the recording setup is built just by a transmittance SLM and an image sensor. The tested wavefront incident to the SLM plane can be quantitatively retrieved from the diffraction intensities of the wavefront passed through the SLM displaying a IBRS pattern. Because only two modulation states (opaque and transparent) of the SLM are used, the method does not need to know the concrete modulation function of the SLM in advance. In addition by introducing the concept of the incremental random sampling into wavefront sensing, the adaptability of phase retrieving based on the diffraction intensities is significantly improved. To the best of our knowledge, no previous study has used this concept for the same purpose. Some experimental results are given for demonstrating the feasibility of our method.
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Thalidomide (THD) is an immunomodulatory agent used to treat immune-mediated diseases. Immune thrombocytopenia (ITP) is an autoimmune disorder in which impaired mesenchymal stem cells (MSCs) are potentially involved. We demonstrated that MSCs in ITP patients had reduced proliferative capacity and lost their immunosuppressive function, which could be corrected with THD treatment. According to the gene profile, the downregulation of caspase-8 and caspase-10, and upregulation of oct3/4 and tgf-ß1, may be associated with THD modulation. Dendritic cells (DCs) played an important role in mediating the inhibitory activity of MSCs. To study the functional alteration of DCs elicited by MSCs, we sorted DCs after incubation with MSCs and performed T-lymphocyte reaction assays. The THD-modulated MSCs from ITP patients induced mature DCs to become tolerogenic DCs, whereas unmodulated MSCs had no effect. The induction of tolerogenicity in DCs by MSCs was dependent on the expression of TIEG1 in DCs. The study reveals the inability of MSCs from ITP patients to induce tolerogenic ability in DCs. THD could restore the regulatory effect of MSCs on DCs. These findings will help us understand the pathogenesis of ITP, and with appropriate safeguards, THD may benefit patients with ITP.
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Células Dendríticas/imunologia , Tolerância Imunológica/efeitos dos fármacos , Imunossupressores/farmacologia , Células-Tronco Mesenquimais/metabolismo , Púrpura Trombocitopênica Idiopática/imunologia , Púrpura Trombocitopênica Idiopática/metabolismo , Talidomida/farmacologia , Adolescente , Adulto , Idoso , Estudos de Casos e Controles , Proliferação de Células/efeitos dos fármacos , Fatores de Transcrição de Resposta de Crescimento Precoce/genética , Fatores de Transcrição de Resposta de Crescimento Precoce/metabolismo , Feminino , Perfilação da Expressão Gênica , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Fatores de Transcrição Kruppel-Like/genética , Fatores de Transcrição Kruppel-Like/metabolismo , Masculino , Pessoa de Meia-Idade , Púrpura Trombocitopênica Idiopática/genética , Interferência de RNA , Adulto JovemRESUMO
We proposed an iterative method for phase retrieval and diffractive imaging based on Babinet's principle and complementary random sampling (CRS). We demonstrated that the whole complex amplitude (not sieved) of an object wave can be accurately retrieved from the diffraction intensities of the object wave sampled by a group of binary CRS masks and the diffractive imaging for the object can be realized through a single digital inverse diffraction. Some experimental results are given for the demonstration. Our experimental results reveal that, using CRS, the influence of a binary random sampling mask on the retrieved field can be well eliminated, and the accuracy and efficiency of the phase retrieval can be greatly improved.
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The evolutionary and statistical properties of the optical vortices that exist in random nondiffracting beams (RNDBs) are analyzed. It is found that the phase singularities (PSs) in the RNDBs originate from the zero rings of Bessel beams with the same ring-shaped spatial spectrum structure (but with zero phase fluctuations) as those of the RNDBs provided. It is also found that the average PS density or vortex density is determined by the average duration of the zero rings of the corresponding Bessel function. According to this model, we successfully derived, for the first time to our knowledge, an analytical formula for quantitatively predicting the PS density of the RNDBs. This formula could be helpful for understanding and designing RNDBs in their applications.
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A simple and practical system for generation of vector beams with arbitrary polarization and complex-amplitude distributions is proposed. The system mainly consists of a scalar computer-generated hologram (CGH), a small-angle birefringent beam splitter (BBS), and a Fourier lens with a filtering aperture (FA). The CGH is placed in front of the Fourier lens. The BBS is inserted between the CGH and the Fourier lens. When the CGH specially designed according to the method described in this Letter is illuminated by a plane beam or a Gaussian beam, a desired vector beam can be obtained through the FA placed at the back focal plane of the Fourier lens. Because no coupling element and half-wave plate are to be placed between the CGH and the BBS, the extinction ratios of both the two orthogonal polarization components for the vector beam can be better than 10(-5) and so high-quality vector beams can be generated.
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Optical vortex beams propagating through atmospheric turbulence are studied by numerical modeling, and the phase singularities of the vortices existing in the turbulence-distorted beams are calculated. It is found that the algebraic sum of topological charges (TCs) of all the phase singularities existing in test aperture is approximately equal to the TC of the input vortex beam. This property provides us a possible approach for determining the TC of the vortex beam propagating through the atmospheric turbulence, which could have potential application in optical communication using optical vortices.
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A common-path and on-axis configuration for improving the resolution power of a lensless Fresnel holographic imaging system is proposed. In this configuration, a pinhole array plate (PAP) is inserted between the object and the recording plane. We demonstrated that the complex amplitude of the object wave can be directly extracted from a single Fresnel hologram of the object wave sampled by the PAP, and the numerical aperture of the effective imaging system can be increased because of the diffraction effect of the pinhole array. It may provide one approach for improving the capabilities of digital holography available for a wide range of wavelengths from far-infrared to x-ray and electron beams.
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Evolution of branch points in the distorted optical field is studied when a laser beam propagates through turbulent atmosphere along an uplink path. Two categories of propagation events are mainly explored for the same propagation height: fixed wavelength with change of the turbulence strength and fixed turbulence strength with change of the wavelength. It is shown that, when the beam propagates to a certain height, the density of the branch-points reaches its maximum and such a height changes with the turbulence strength but nearly remains constant with different wavelengths. The relationship between the density of branch-points and the Rytov number is also given. A fitted formula describing the relationship between the density of branch-points and propagation height with different turbulence strength and wavelength is found out. Interestingly, this formula is very similar to the formula used for describing the Blackbody radiation in physics. The results obtained may be helpful for atmospheric optics, astronomy and optical communication.
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A flexible approach is presented to generate vector beams with arbitrary polarization and complex amplitude by means of two cascaded transmissive liquid crystal spatial light modulators (LCSLMs). The configuration of the cascaded LCSLM system and its modulation characteristic are introduced. Theoretical analysis and experimental demonstration prove that the system in combination with a double-pass computer-generated hologram and a black-and-white pattern can generate vector beams with arbitrary polarization and complex amplitude by respectively controlling the complex amplitudes of two orthogonal polarization components of the beams. Using this system, we successfully generate radially polarized vector beams with helical phase distributions and vector Bessel beams with inhomogeneous amplitude distributions in experiments.