Journals >Chinese Optics Letters
Contents
2010
Volume: 8 Issue 10
26 Article(s)
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Research Article
Fluorescence lifetime imaging of molecular rotors to map microviscosity in cells (Invited Paper)
James A. Levitt, Marina K. Kuimova, Gokhan Yahioglu, Pei-Hua Chung, Klaus Suhling, and David Phillips
Fluorescence liftime imaging (FLIM) of modified hydrophobic bodipy dyes that act as fluorescent molecular rotors shows that the fluorescence lifetime of these probes is a function of the microviscosity of their environment. Incubating cells with these dyes, we find a punctate and continuous distribution of the dye in cFluorescence liftime imaging (FLIM) of modified hydrophobic bodipy dyes that act as fluorescent molecular rotors shows that the fluorescence lifetime of these probes is a function of the microviscosity of their environment. Incubating cells with these dyes, we find a punctate and continuous distribution of the dye in cells. The viscosity value obtained in what appears to be endocytotic vesicles in living cells is around 100 times higher than that of water and of cellular cytoplasm.Time-resolved fluorescence anisotropy measurements also yield rotational correlation times consistent with large microviscosity values. In this way, we successfully develop a practical and versatile approach to map the microviscosity in cells based on imaging fluorescent molecular rotors..
Chinese Optics Letters
- Publication Date: Jul. 07, 2021
- Vol. 8, Issue 10, 926 (2010)
Monitoring cellular metabolism of 3T3 upon wild type E. coli infection by mapping NADH with FLIM (Invited Paper)
Tatyana Buryakina, Pin-Tzu Su, Vladimir Gukassyan, Wan-Jr Syu, and Fu-Jen Kao
Fluorescence lifetime imaging microscopy (FLIM) has gained popularity as a sensitive technique to monitor the functional/conformational states of reduced nicotinamide adenine dinucleotide (NADH), one of the main compounds of oxidative phosphorylation. In this letter, we apply the technique to characterize the metabolicFluorescence lifetime imaging microscopy (FLIM) has gained popularity as a sensitive technique to monitor the functional/conformational states of reduced nicotinamide adenine dinucleotide (NADH), one of the main compounds of oxidative phosphorylation. In this letter, we apply the technique to characterize the metabolic changes in mouse embryonic fibroblast 3T3 cells upon bacterial infection. A gradual shortening of the decaying time constants in both the short and the long lifetime components of NADH’s autofluorescence is detected. The ratio of the short and the long lifetime components’ relative contributions, however, shows a rapid increase, indicating the rise of cellular metabolic activity over the course of infection..
Chinese Optics Letters
- Publication Date: Jul. 07, 2021
- Vol. 8, Issue 10, 931 (2010)
Improving the precision of fluorescence lifetime measurement using a streak camera
Heng Li, Yonghong Shao, Yan Wang, Junle Qu, and Hanben Niu
Streak camera has high temporal resolution and high sensitivity, and is a powerful tool in biomedical study to measure fluorescence lifetime and perform fluorescence lifetime imaging. However, nonuniformity of the gain in the streak tube and nonlinearity of the sweeping speed limit the precision of fluorescence lifetimStreak camera has high temporal resolution and high sensitivity, and is a powerful tool in biomedical study to measure fluorescence lifetime and perform fluorescence lifetime imaging. However, nonuniformity of the gain in the streak tube and nonlinearity of the sweeping speed limit the precision of fluorescence lifetime measurement, particularly when fluorescence lifetimes are short. We have constructed a twophoton excitation fluorescence lifetime measurement system that is based on a synchroscan streak camera and have developed accordingly a method to correct the effect of gain nonuniformity and nonlinearity of sweeping speed on the measurement precision. A continuous-wave laser of high stability is used to calibrate the gain of the streak camera, and a Fabry-Perot etalon is used to calibrate the nonlinearity of the sweeping speed. Fitting algorithms are used to correct the gain of the streak camera and nonlinearity of the sweeping speed respectively, which significantly improves the measurement precision of the system, as characterized through the fluorescence lifetime of the short-lived fluorescence dye, Rose Bengal. Experimental results show that the measurement fluctuation of the lifetime has been improved from more than 10% to 2% after correcting the effects of gain nonuniformity and sweeping speed nonlinearity..
Chinese Optics Letters
- Publication Date: Jul. 07, 2021
- Vol. 8, Issue 10, 934 (2010)
Spectral imaging of time-resolved anisotropy: theory and experiment
Yanzhou Zhou, Qingruo Wang, Jingsong He, and Lerong Lin
Time-resolved fluorescence anisotropy on the nanosecond time scale is useful for the study of the rapid rotation of macromolecules. A system combining the capabilities of fluorescence spectral imaging with time-resolved fluorescence anisotropy and enabling the wide-field measurement of the spectroscopic parameters of fTime-resolved fluorescence anisotropy on the nanosecond time scale is useful for the study of the rapid rotation of macromolecules. A system combining the capabilities of fluorescence spectral imaging with time-resolved fluorescence anisotropy and enabling the wide-field measurement of the spectroscopic parameters of fluorophores is discussed. The phasor approach is used to quantitatively analyze the time-resolved fluorescence anisotropy by transforming the polarized parallel and perpendicular components to the phasor space in the frequency domain, respectively, and a unique way to calculate the fluorescence rotational correlation time is put forward. Experimental results prove that the phasor approach is a proper model for the time-resolved fluorescence anisotropy..
Chinese Optics Letters
- Publication Date: Jul. 07, 2021
- Vol. 8, Issue 10, 937 (2010)
Uptake of transferrin-conjugated quantum dots in single living cells
Danni Chen, Gaixia Xu, Bahi Ahmed Ali, Ken-Tye Yong, Cuihong Zhou, Xiaomei Wang, Junle Qu, Paras N. Prasad, and Hanben Niu
We study the uptake and distribution of transferrin (Tf)-conjugated CdSe/CdS/ZnS quantum dots (QDs) in single living HeLa cells with both fluorescence confocal microscopy and three-dimensional (3D) reconstruction technique. By increasing the co-incubation time or the dosage of QDs-Tf, we find that the uptake of QDs-Tf We study the uptake and distribution of transferrin (Tf)-conjugated CdSe/CdS/ZnS quantum dots (QDs) in single living HeLa cells with both fluorescence confocal microscopy and three-dimensional (3D) reconstruction technique. By increasing the co-incubation time or the dosage of QDs-Tf, we find that the uptake of QDs-Tf bioconjugates in the cells increases correspondingly, but with different uptake rates. Additionally, the distribution of QDs-Tf, in single live HeLa cells is time dependent. To our knowledge, this is the first study on quantitatively analyzing the uptake and distribution of bioconjugated QDs in single living cells. Such QDs nanoplatform can be further modified for developing biomedical evaluation tool in cancer diagnosis and targeted drug delivery..
Chinese Optics Letters
- Publication Date: Jul. 07, 2021
- Vol. 8, Issue 10, 940 (2010)
A miniature laser speckle fluorescence sectioning microscope for cell imaging
Yonghong Shao, Heng Li, Qiao Wen, Yan Wang, Junle Qu, and Hanben Niu
We present a miniature fluorescence sectioning microscope which uses a diode-pumped solid-state (DPSS) laser as the light source and a fast translating diffuser to produce dynamically changing speckle patterns onto the back aperture of the objective to illuminate the sample. Optical sectioning, which originates from thWe present a miniature fluorescence sectioning microscope which uses a diode-pumped solid-state (DPSS) laser as the light source and a fast translating diffuser to produce dynamically changing speckle patterns onto the back aperture of the objective to illuminate the sample. Optical sectioning, which originates from the statistical characteristics of laser speckles, is obtained by calculating the contrast of a series of fluorescence images. High contrast fluorescence sectioning images of bovine pulmonary artery endothelial (BPAE) cells are obtained. The image quality is similar to that of the images acquired by standard laser scanning confocal microscope (LSCM). Compared with LSCM, the laser speckle fluorescence microscope (LSFM) presented in this letter has many advantages, such as simple configurations, low cost, compact, and easy to operate, which makes it possible to have wide spread applications in biomedicine..
Chinese Optics Letters
- Publication Date: Jul. 07, 2021
- Vol. 8, Issue 10, 944 (2010)
Improving FRET efficiency measurement in confocal microscopy imaging
Huaina Yu, Tongsheng Chen, and Junle Qu
Spectral bleedthrough (SBT) ratio is dependent on the level of fluorescence intensity in confocal imaging. Precision Forster resonance energy transfer (FRET) algorithm corrects SBT ratio according to fluorescence intensity and avoids over- or under-estimation of SBT ratio. In this letter, we propose a new method to accSpectral bleedthrough (SBT) ratio is dependent on the level of fluorescence intensity in confocal imaging. Precision Forster resonance energy transfer (FRET) algorithm corrects SBT ratio according to fluorescence intensity and avoids over- or under-estimation of SBT ratio. In this letter, we propose a new method to accurately measure the FRET efficiency of FRET plasmid in single living cells by combining the calculation of SBT in precision FRET algorithm with E-FRET formulae. We also use this method to measure the FRET efficiency of FRET-Bid, and find that in healthy A549 cells it is about 15%, which is verified by FRET acceptor photobleaching method..
Chinese Optics Letters
- Publication Date: Jul. 07, 2021
- Vol. 8, Issue 10, 947 (2010)
Confocal imaging of Bim translocation to endoplasmic reticulum during DHA-induced ASTC-a-1 cell apoptosis
Min Chen, Yingying Lu, Tongsheng Chen, and Junle Qu
Bim, a proapoptotic member of Bcl-2 family, plays an important role in cell apoptosis. It is generally thought that Bim translocates to mitochondria in response to apoptotic stimuli. We use confocal microscopy to image the temporal-spatial dynamics of Bim during dihydroartemisinin (DHA) induced human lung adenocarcinomBim, a proapoptotic member of Bcl-2 family, plays an important role in cell apoptosis. It is generally thought that Bim translocates to mitochondria in response to apoptotic stimuli. We use confocal microscopy to image the temporal-spatial dynamics of Bim during dihydroartemisinin (DHA) induced human lung adenocarcinoma (ASTC-a-1) cell apoptosis. Interestingly, we find that DHA induces Bim translocation to endoplasmic reticulum (ER) rather than mitochondria, implying that Bim-ER pathway might be involved in the DHA-induced ASTC-a-1 cell apoptosis..
Chinese Optics Letters
- Publication Date: Jul. 07, 2021
- Vol. 8, Issue 10, 950 (2010)
Circulation times of hepatocellular carcinoma cells by in vivo flow cytometry
Yan Li, Zhichao Fan, Jin Guo, Guangda Liu, Xiaoying Tan, Cheng Wang, Zhengqin Gu, and Xunbin Wei
Hepatocellular carcinoma (HCC) may metastasize to many organs. The survival rate is almost zero for metastatic HCC patients. Molecular mechanisms of HCC metastasis need to be understood better and new therapies must be developed. We have developed the "in vivo microscopy" to study the mechanisms that govern lHepatocellular carcinoma (HCC) may metastasize to many organs. The survival rate is almost zero for metastatic HCC patients. Molecular mechanisms of HCC metastasis need to be understood better and new therapies must be developed. We have developed the "in vivo microscopy" to study the mechanisms that govern liver tumor cells spreading through the microenvironment in vivo. A recently developed "in vivo flow cytometer" combined with real-time confocal fluorescence imaging is used to assess spreading and the circulation kinetics of liver tumor cells. We measure the depletion kinetics of two related human HCC cell lines, high-metastatic HCCLM3 cells and low-metastatic HepG2 cells, which are from the same origin and obtained by repetitive screenings in mice. More than 60% of the HCCLM3 cells are depleted within the first hour. Interestingly, the low-metastatic HepG2 cells possess noticeably slower depletion kinetics. In comparison, less than 40% of the HepG2 cells are depleted within the first hour. The differences in depletion kinetics might provide insights into early metastasis processes..
Chinese Optics Letters
- Publication Date: Jul. 07, 2021
- Vol. 8, Issue 10, 953 (2010)
Design and fabrication of automated sedimentation-based separation and siphon-based extraction for detection of allergic reaction on a centrifugal microfluidic disc (Invited Paper)
Q. L. Chen, H. P. Ho, K. L. Cheung, S. K. Kong, Y. K. Suen, Y. W. Kwan, and C. K. Wong
We report the design and fabrication of a novel and fully integrated polymer-based centrifugal microfluidic disc for rapid automatic allergens detection. All essential steps for a single test including flow valving, sequencing, mixing, separation, extraction, and sedimentation for final detection are automatically condWe report the design and fabrication of a novel and fully integrated polymer-based centrifugal microfluidic disc for rapid automatic allergens detection. All essential steps for a single test including flow valving, sequencing, mixing, separation, extraction, and sedimentation for final detection are automatically conducted within 30 min on a centrifugal microfluidic disc. Our design features a siphon-based valving and analyte extraction structure where the released analyte is separated and subsequently extracted by a siphon valve into the detection chamber. Incorporating the siphon valve and a series of capillary valves, we realize automated detection of allergic reaction on a centrifugal microfluidic disc..
Chinese Optics Letters
- Publication Date: Jul. 07, 2021
- Vol. 8, Issue 10, 957 (2010)
Simulation and optimization of spatial light modulation of twisted-nematic liquid crystal display
Baiheng Ma, Baoli Yao, Shaohui Yan, Fei Peng, Junwei Min, Ming Lei, and Tong Ye
The approaches to obtaining desired intensity or phase modulation by twisted-nematic liquid crystal display (TN-LCD) have been extensively studied based on the knowledge of the LCD's internal structure parameters. Generally, the TN-LCD placed between two linear polarizers (P) produces coupled intensity and phase moThe approaches to obtaining desired intensity or phase modulation by twisted-nematic liquid crystal display (TN-LCD) have been extensively studied based on the knowledge of the LCD's internal structure parameters. Generally, the TN-LCD placed between two linear polarizers (P) produces coupled intensity and phase modulation. To obtain the commonly used phase-only modulation, quarter wave plates (QWPs) are often used in front of and/or behind the LCD. Here we present a method to optimize the optical modulation properties of the TN-LCD to obtain phase-only modulation in the configuration of P-QWP-LCD-QWP-P each with proper orientation. Our method is based on the macroscopical Jones matrix descriptions for the LCD, the QWPs, and the linear polarizers. Through Jones matrix calculations, the orientations of the polarizers and QWPs can be optimized to satisfy differently desired modulation demands. In contrast to the traditional method, which requires knowledge of the LCD's internal structure parameters, our method simplified the complicated theory analysis and can work in the absence of information on the LCD's internal structure parameters, which are usually not available for the commercial products..
Chinese Optics Letters
- Publication Date: Jul. 07, 2021
- Vol. 8, Issue 10, 960 (2010)
A new visual investigation into nanogold-based genechip assay by atomic force and scanning tunneling microscope
Dayong Gu, Weidong Xie, Zhen Li, Weiping Lu, Yuanguo Zhou, and Minghui Ji
Conformations of surface atoms in various stages of nanogold-based genechip testing are scanned by the atomic force and scanning tunneling microscope. We intuitively observe the process and differences in probe combination, nucleic acid hybridization, and silver staining, which might be useful to validate the assay metConformations of surface atoms in various stages of nanogold-based genechip testing are scanned by the atomic force and scanning tunneling microscope. We intuitively observe the process and differences in probe combination, nucleic acid hybridization, and silver staining, which might be useful to validate the assay method of genechip. We hope to use this technology to make the other invisible chemical or biochemical reaction become visible and convincible in the future..
Chinese Optics Letters
- Publication Date: Jul. 07, 2021
- Vol. 8, Issue 10, 964 (2010)
37-element solar adaptive optics for 26-cm solar fine structure telescope at Yunnan Astronomical Observatory
Changhui Rao, Lei Zhu, Xuejun Rao, Chunlin Guan, Donghong Chen, Jun Lin, and Zizhong Liu
A 37-element solar adaptive optics (AO) system was built and installed at the 26-cm solar fine structure telescope of Yunnan Astronomical Observatory. The AO system is composed of a fine tracking loop with a tip/tilt mirror and a correlation tracker, a high-order correction loop with a 37-element deformable mirror, a cA 37-element solar adaptive optics (AO) system was built and installed at the 26-cm solar fine structure telescope of Yunnan Astronomical Observatory. The AO system is composed of a fine tracking loop with a tip/tilt mirror and a correlation tracker, a high-order correction loop with a 37-element deformable mirror, a correlating Shack-Hartmann wavefront sensor based on the absolute difference algorithm, and a real time controller. The system was completed on Sep. 28, 2009 and was used to obtain AO-corrected highresolution solar images. The contrast and resolution of the images are clearly improved after wavefront correction by AO. To the best of out knowledge, this system is the first solar AO system in China..
Chinese Optics Letters
- Publication Date: Jul. 07, 2021
- Vol. 8, Issue 10, 966 (2010)
Novel WDM-PON architecture for simultaneous transmission of unicast data and multicast services
Min Zhu, Shilin Xiao, Wei Guo, Weisheng Hu, and Benoit Geller
We propose a novel wavelength-division multiplexed passive optical network (WDM-PON) to simultaneously transmit unicast data and multicast services with upstream data re-modulation in optical network units (ONUs). For each wavelength channel in the optical line terminal (OLT), the downstream unicast data are applied toWe propose a novel wavelength-division multiplexed passive optical network (WDM-PON) to simultaneously transmit unicast data and multicast services with upstream data re-modulation in optical network units (ONUs). For each wavelength channel in the optical line terminal (OLT), the downstream unicast data are applied to one arm of a dual-parallel Mach-Zehnder modulator (DPMZM) to generate baseband unicast non-return-to-zero (NRZ) signal. A radio frequency (RF) control signal is applied to the other arm to present two un-modulated sidebands for multicast data modulation in a differential phase-shift keying (DPSK) format. The flexible and dynamic multicast services are realized by simply switching the RF control signal on or off. The proposed scheme is experimentally demonstrated with 1.25-Gb/s downstream unicast, multicast, and upstream data..
Chinese Optics Letters
- Publication Date: Jul. 07, 2021
- Vol. 8, Issue 10, 972 (2010)
40-Gb/s PolMux-QPSK transmission using low-voltage modulation and single-ended digital coherent detection
Yong Feng, He Wen, Hanyi Zhang, and Xiaoping Zheng
We demonstrate a novel 40-Gb/s transmission system over a 10×101-km standard single mode fiber (SSMF) loop. This system features polarization multiplexed quadrature phase shift keying (PolMux-QPSK), lowvoltage modulation of 2-V peak-to-peak signal amplitude, and home-made 90? optical hybrid with singleended digitaWe demonstrate a novel 40-Gb/s transmission system over a 10×101-km standard single mode fiber (SSMF) loop. This system features polarization multiplexed quadrature phase shift keying (PolMux-QPSK), lowvoltage modulation of 2-V peak-to-peak signal amplitude, and home-made 90? optical hybrid with singleended digital coherent detection. Any power amplifers before the modulator and balanced detectors are not used. In the case of low-voltage modulation, coherent detection is much less sensitive to modulator bias offset than delay interferometer-based demodulation..
Chinese Optics Letters
- Publication Date: Jul. 07, 2021
- Vol. 8, Issue 10, 976 (2010)
An all-optical polarization monitoring scheme for polarization division multiplexed transmission
Jia Ye, Lianshan Yan, Anlin Yi, Wei Pan, Bin Luo, Zhen Guo, and X. Steve Yao
A novel polarization monitoring scheme for polarization division multiplexed (PDM) systems is proposed. By using a tag light transmitted in different but close wavelength to the data signal as the feedback control, the scheme can demultiplex automatically two orthogonal polarizations in PDM systems. The effectiveness oA novel polarization monitoring scheme for polarization division multiplexed (PDM) systems is proposed. By using a tag light transmitted in different but close wavelength to the data signal as the feedback control, the scheme can demultiplex automatically two orthogonal polarizations in PDM systems. The effectiveness of the scheme is demonstrated experimentally in a 2￡10-Gb/s on-off-keying (OOK) PDM transmission system..
Chinese Optics Letters
- Publication Date: Jul. 07, 2021
- Vol. 8, Issue 10, 979 (2010)
Equal channel spacing Sagnac filter using high-birefringent photonic crystal fibers
Xiurong Ma, and Ying Zhu
An equal channel spacing Sagnac filter is proposed using a high-birefringent photonic crystal fiber (PCF) with birefringence square to the operation wavelength. A PCF with four smaller central air holes surrounded by larger air holes is applied in a Sagnac filter with optimized parameters to achieve equal channel spaciAn equal channel spacing Sagnac filter is proposed using a high-birefringent photonic crystal fiber (PCF) with birefringence square to the operation wavelength. A PCF with four smaller central air holes surrounded by larger air holes is applied in a Sagnac filter with optimized parameters to achieve equal channel spacing of 0.8 nm. Given that the birefringence of this PCF is square to the operation wavelength, the channel spacing of the proposed filter changes by only 0.03 nm within a wavelength range from 1400 to 1650 nm; this is about one order of magnitude less than that constructed with conventional high-birefringent fibers..
Chinese Optics Letters
- Publication Date: Jul. 07, 2021
- Vol. 8, Issue 10, 983 (2010)
Novel modal interferometer based on ring-core photonic crystal fiber
Weiguo Chen, Shuqin Lou, Liwen Wang, and Shuisheng Jian
An original design of ring-core photonic crystal fiber (RPCF) is proposed. By splicing a section of the homemade RPCF between two segments of single mode fibers (SMFs), a simple modal interferometer is presented and experimentally demonstrated. Owing to the effects of the collapsed region, the ring modes in RPCF can beAn original design of ring-core photonic crystal fiber (RPCF) is proposed. By splicing a section of the homemade RPCF between two segments of single mode fibers (SMFs), a simple modal interferometer is presented and experimentally demonstrated. Owing to the effects of the collapsed region, the ring modes in RPCF can be effectively activated. To our knowledge, it is the first time to demonstrate the modal interferometer based on the interference between the ring modes, which is different from the previously reported interferometers based on the interference between core modes or cladding modes. The temperature and strain characteristics of the interferometers with different lengths of RPCF are investigated..
Chinese Optics Letters
- Publication Date: Jul. 07, 2021
- Vol. 8, Issue 10, 986 (2010)
Improved digital processing method used for image motion measurement based on hybrid opto-digital joint transform correlator
Hongwei Yi, Hui Zhao, Yingcai Li, and Desheng Wen
Hybrid opto-digital joint transform correlator (HODJTC) is effective for image motion measurement, but it is different from the traditional joint transform correlator because it only has one optical transform and the joint power spectrum is directly input into a digital processing unit to compute the image shift. The lHybrid opto-digital joint transform correlator (HODJTC) is effective for image motion measurement, but it is different from the traditional joint transform correlator because it only has one optical transform and the joint power spectrum is directly input into a digital processing unit to compute the image shift. The local cross-correlation image can be directly obtained by adopting a local Fourier transform operator. After the pixel-level location of cross-correlation peak is initially obtained, the up-sampling technique is introduced to relocate the peak in even higher accuracy. With signal-to-noise ratio ≥ 20 dB, up-sampling factor k ≥ 10 and the maximum image shift ≤ 60 pixels, the root-mean-square error of motion measurement accuracy can be controlled below 0.05 pixels..
Chinese Optics Letters
- Publication Date: Jul. 07, 2021
- Vol. 8, Issue 10, 989 (2010)
Timing jitter reduction over 20-km urban fiber by compensating harmonic phase difference of locked femtosecond comb
Dong Hou, Peng Li, Peng Xi, Jianye Zhao, and Zhigang Zhang
A novel timing jitter reduction system over a round trip 20-km urban fiber link is reported. The phase difference of the ninth harmonic of a high-repetition-rate mode-locked laser between the local and the returned signals is obtained. Based on the phase difference, the system uses an optical delay line (ODL) to compenA novel timing jitter reduction system over a round trip 20-km urban fiber link is reported. The phase difference of the ninth harmonic of a high-repetition-rate mode-locked laser between the local and the returned signals is obtained. Based on the phase difference, the system uses an optical delay line (ODL) to compensate the optical fiber link. The root-mean-square (RMS) timing jitter is reduced from 50 to 8.9 ps in 80 min..
Chinese Optics Letters
- Publication Date: Jul. 07, 2021
- Vol. 8, Issue 10, 993 (2010)
Analysis and compensation of thermal lens effects in Tm:YAP lasers
Baoquan Yao, Yi Tian, Wei Wang, Gang Li, and Yuezhu Wang
The thermal lens effects in Tm:YAP laser are analyzed by solving the Poisson equation with finite difference method. The thermal focal lengths measured are in the range of 40 ? 90 mm at the pump power of 16?34 W, consistent with the simulation results. The temperature contribution coefficient (the linear coefficient beThe thermal lens effects in Tm:YAP laser are analyzed by solving the Poisson equation with finite difference method. The thermal focal lengths measured are in the range of 40 ? 90 mm at the pump power of 16?34 W, consistent with the simulation results. The temperature contribution coefficient (the linear coefficient between the maximum temperature in the laser crystal and the pump power) of 1.19 K/W is also obtained. The convex lens and plano-concave mirror thermal lens compensation methods are proposed and applied to a high power pumped Tm:YAP laser..
Chinese Optics Letters
- Publication Date: Jul. 07, 2021
- Vol. 8, Issue 10, 996 (2010)
Thermal stress cleaving of silicon wafer by pulsed Nd:YAG laser
Jian Liu, Jian Lu, Xiaowu Ni, Gang Dai, and Liang Zhang
The applied laser energy absorbed in a local area in laser thermal stress cleaving of brittle materials using a controlled fracture technique produces tensile thermal stress that causes the material to separate along the moving direction of the laser beam. The material separation is similar to crack extension, but the The applied laser energy absorbed in a local area in laser thermal stress cleaving of brittle materials using a controlled fracture technique produces tensile thermal stress that causes the material to separate along the moving direction of the laser beam. The material separation is similar to crack extension, but the fracture growth is controllable. Using heat transfer theory, we establish a three-dimensional (3D) mathematical thermoelastic calculational model containing a pre-existing crack for a two-point pulsed Nd:YAG laser cleaving silicon wafer. The temperature field and thermal stress field in the silicon wafer are obtained by using the finite element method (FEM). The distribution of the tensile stress and changes in stress intensity factor around the crack tip are analyzed during the pulse duration. Meanwhile, the mechanism of crack propagation is investigated by analyzing the development of the thermal stress field during the cleaving process..
Chinese Optics Letters
- Publication Date: Jul. 07, 2021
- Vol. 8, Issue 10, 1000 (2010)
Investigation on mode matching including thermal effects in LD end-pumped passively mode-locked Nd:YVO4 laser
Xiapaketi Wushouer, Haijuan Yu, Ping Yan, and Mali Gong
We design a laser diode (LD) end-pumped passively mode-locked solid-state laser with a semiconductor saturable absorber mirror. Mode-matching efficiency in the active medium including the thermal effect is analyzed, and the optimum mode-matching coefficient is obtained by optimizing the pump mode. In the experiment, a We design a laser diode (LD) end-pumped passively mode-locked solid-state laser with a semiconductor saturable absorber mirror. Mode-matching efficiency in the active medium including the thermal effect is analyzed, and the optimum mode-matching coefficient is obtained by optimizing the pump mode. In the experiment, a total power of 4.2 W stable pulse sequences without multipulse at 1064 nm is obtained with a pulse repetition rate of 86 MHz and a pulse width of 13 ps, corresponding to a high optical to optical efficiency of 44%..
Chinese Optics Letters
- Publication Date: Jul. 07, 2021
- Vol. 8, Issue 10, 1004 (2010)
Improvement of the large aperture Ti:sapphire amplif iers in the petawatt femtosecond laser system at SIOM
Xiaoming Lu, Xiaoyan Liang, Yuxin Leng, Wenyao Wang, Cheng Wang, Dingjun Yin, Haihe Lu, Ruxin Li, and Zhizhan Xu
We report the recent improvement on the petawatt (PW) femtosecond Ti:sapphire chirped pulse amplification (CPA) laser system at Shanghai Institute of Optics and Fine Mechanics (SIOM), Chinese Academy of Sciences. By enlarging the sizes of the pump and signal beams in the large aperture Ti:sapphire amplifiers and optimiWe report the recent improvement on the petawatt (PW) femtosecond Ti:sapphire chirped pulse amplification (CPA) laser system at Shanghai Institute of Optics and Fine Mechanics (SIOM), Chinese Academy of Sciences. By enlarging the sizes of the pump and signal beams in the large aperture Ti:sapphire amplifiers and optimizing the whole laser system, the output laser energy before the pulse compressor is upgraded to 42.6 J. Accordingly, the peak power of the laser system exceeds 1 PW. The shot-to-shot instability of the output laser energy at about 40 J is less than ±5%..
Chinese Optics Letters
- Publication Date: Jul. 07, 2021
- Vol. 8, Issue 10, 1008 (2010)
Sparse Bayesian reconstruction method for multispectral bioluminescence tomography
Jinchao Feng, Kebin Jia, Chenghu Qin, Shouping Zhu, Xin Yang, and Jie Tian
We present a sparse Bayesian reconstruction method based on multiple types of a priori information for multispectral bioluminescence tomography (BLT). In the Bayesian approach, five kinds of a priori information are incorporated, reducing the ill-posedness of BLT. Specifically, source sparsity characteristic is consideWe present a sparse Bayesian reconstruction method based on multiple types of a priori information for multispectral bioluminescence tomography (BLT). In the Bayesian approach, five kinds of a priori information are incorporated, reducing the ill-posedness of BLT. Specifically, source sparsity characteristic is considered to promote reconstruction results. Considering the computational burden in the multispectral case, a series of strategies is adopted to improve computational efficiency, such as optimal permissible source region strategy and node model of the finite element method. The performance of the proposed algorithm is validated by a heterogeneous three-dimensional (3D) micron scale computed tomography atlas and a mouse-shaped phantom. Reconstructed results demonstrate the feasibility and effectiveness of the proposed algorithm..
Chinese Optics Letters
- Publication Date: Jul. 07, 2021
- Vol. 8, Issue 10, 1010 (2010)
Investigation on activating individual living monocytic U937 cell by interleukin-6 using Raman tweezers
Yule Xiong, Anpei Ye, Cheng Wen, and Yong Zhang
We investigate the activation of living monocytic U937 cells induced by interleukin-6 (IL-6) at the single cell level. We employ home-built Raman tweezers to measure the Raman spectra of living U937 cells with and without IL-6 at the single cell level. Raman peaks of amide III, amide I, DNA backbone, as well as guanineWe investigate the activation of living monocytic U937 cells induced by interleukin-6 (IL-6) at the single cell level. We employ home-built Raman tweezers to measure the Raman spectra of living U937 cells with and without IL-6 at the single cell level. Raman peaks of amide III, amide I, DNA backbone, as well as guanine and adenine in U937 cells, change at 1312, 1652, 1090, and 1576 cm ?1, respectively, shortly after IL-6 is added in the medium. The change is a dynamic temporal process. In the activation process of U937 cells induced by IL-6, the protein signals recover in 20 min, while the nucleic acid signals continue to increase for 20 min. The results reveal that the biochemical cascades of activation in signal transduction induced by IL-6 can be investigated in situ at the single cell level..
Chinese Optics Letters
- Publication Date: Jul. 07, 2021
- Vol. 8, Issue 10, 1015 (2010)
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