Fabrication method and device of ultra-small gradient-index （GRIN） fiber probe were investigated in order to explore the development of ultra-small probes for optical coherence tomography （OCT） imaging. The beam- ...Fabrication method and device of ultra-small gradient-index （GRIN） fiber probe were investigated in order to explore the development of ultra-small probes for optical coherence tomography （OCT） imaging. The beam- expanding effect of no-core fiber （NCF） and the focusing properties of the GRIN fiber lens were analyzed based on the model of GRIN fiber probe consisting of single-mode fiber （SMF）, NCF and GRIN fiber lens. A stereo micro- scope based system was developed to fabricate the GRIN fiber probe. A fiber fusion splicer and an ultrasonic cleaver were used to weld and cut the fiber respectively. A con- focal microscopy was used to measure the dimensions of probe components. The results show that the sizes of probe components developed are at the level of millimeter. Therefore, the proposed experimental system meets the fabrication requirements of an ultra-small self-focusing GRIN fiber probe. This shows that this fabrication device and method can be employed in the fabrication of ultra- small self-focusing GRIN fiber probe and applied in the study of miniaturized optical probes and OCT systems.展开更多
With the rapid development of life sciences, there is an increasing demand for intravital fluorescence imaging of small animals. However, large dimensions and limited working distances of objective lenses in tradition...With the rapid development of life sciences, there is an increasing demand for intravital fluorescence imaging of small animals. However, large dimensions and limited working distances of objective lenses in traditional fluorescence microscopes have limited their imaging applications mostly to superficial tissues. To overcome these disadvantages, researchers have developed the graded-index （GRIN） probes with small diameters for imaging internal organs of small animals in a minimally invasive fashion. However, dynamic imaging based on GRIN lens has not been studied extensively. Here, this paper presented a fluorescence endoscopic imaging system based on GRiN lenses using one-photon and two-photon excitation. GRIN lenses with 1.15 mm diameter and 7.65 mm length were used in the system. The images were acquired by a compact laser scanning imaging system with a resonant galvo-mirror system to scan the laser beam and a photomultiplier tube （PMT） to detect fluorescence signals. Experimental results showed that this system using two-photon excitation could implement dynamic fluorescence microendoscopic imaging and monitor the movement of blood flow beneath the skin in anesthetized mice while producing images with higher contrast and signal to noise ratio （SNR） than those using one photon excitation. It would be a useful tool for studying biological processes of small animals or plants in vivo.展开更多
In this paper, a polymer spherical symmetry GRIN sphere lens were prepared by the suspension-diffusion-copolymerization(SDC) technique, selecting methyl methacrylate(MMA) as monomer M1 and acrylic 2,2,2-trifluoroethyl...In this paper, a polymer spherical symmetry GRIN sphere lens were prepared by the suspension-diffusion-copolymerization(SDC) technique, selecting methyl methacrylate(MMA) as monomer M1 and acrylic 2,2,2-trifluoroethyl ester(3FEA) as M2. The radial distribution of refractive index of the lens was measured by the shearing interference method, which demonstrated that the quadratic refractive-index distribution was formed in the sphere lens, and its Δn=0.019.展开更多
The beams of 980nm high-power LDs are analyzed, and the reasons that aspect ratio of LD beams is high are explained. It is certified by the test that cylindrical lens can efficiently compress the perpendicular diverge...The beams of 980nm high-power LDs are analyzed, and the reasons that aspect ratio of LD beams is high are explained. It is certified by the test that cylindrical lens can efficiently compress the perpendicular divergence angle of the beam. Some typical and popular lensed fibers were compared and analyzed according to coupling characteristics. The factors which affect the coupling efficiency and tolerance of the wedged-shaped GRIN tipped lensed fiber are pointed out, and some methods to reduce the coupling loss of the lensed fibers are proposed finally.展开更多
Fllowing the derivation of equations for ray propagation in anisotropic medium, the equations for determinining the ray path featuring progressively increasing and decreasing distribution of index of refraction are pr...Fllowing the derivation of equations for ray propagation in anisotropic medium, the equations for determinining the ray path featuring progressively increasing and decreasing distribution of index of refraction are presented’ With computer the actual ray path can be trced and positions of both observation and image points can be quantitatively indicated for direct perceiving tbe mirage formation. At the end a discussion of the mirage observation zone is attached.展开更多
The complex spatial and temporal organization of neural activity in the brain is important for informationprocessing that guides behavior. Hence, revealing the realtime neural dynamics in freely-moving animals is fund...The complex spatial and temporal organization of neural activity in the brain is important for informationprocessing that guides behavior. Hence, revealing the realtime neural dynamics in freely-moving animals is fundamental to elucidating brain function. Miniature fluorescence microscopes have been developed to fulfil this requirement. With the help of GRadient INdex(GRIN)lenses that relay optical images from deep brain regions to the surface, investigators can visualize neural activity during behavioral tasks in freely-moving animals. However, the application of GRIN lenses to deep brain imaging is severely limited by their availability. Here, we describe a protocol for GRIN lens coating that ensures successful long-term intravital imaging with commercially-available GRIN lenses.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.41104065)the Dawn Planning Foundation of Shanghai Municipal Education Commission (Grant No.12CG047)by the Scientific Research Innovation Project of Shanghai Municipal Education Commission(Grant No. 13YZ022)
文摘Fabrication method and device of ultra-small gradient-index （GRIN） fiber probe were investigated in order to explore the development of ultra-small probes for optical coherence tomography （OCT） imaging. The beam- expanding effect of no-core fiber （NCF） and the focusing properties of the GRIN fiber lens were analyzed based on the model of GRIN fiber probe consisting of single-mode fiber （SMF）, NCF and GRIN fiber lens. A stereo micro- scope based system was developed to fabricate the GRIN fiber probe. A fiber fusion splicer and an ultrasonic cleaver were used to weld and cut the fiber respectively. A con- focal microscopy was used to measure the dimensions of probe components. The results show that the sizes of probe components developed are at the level of millimeter. Therefore, the proposed experimental system meets the fabrication requirements of an ultra-small self-focusing GRIN fiber probe. This shows that this fabrication device and method can be employed in the fabrication of ultra- small self-focusing GRIN fiber probe and applied in the study of miniaturized optical probes and OCT systems.
文摘With the rapid development of life sciences, there is an increasing demand for intravital fluorescence imaging of small animals. However, large dimensions and limited working distances of objective lenses in traditional fluorescence microscopes have limited their imaging applications mostly to superficial tissues. To overcome these disadvantages, researchers have developed the graded-index （GRIN） probes with small diameters for imaging internal organs of small animals in a minimally invasive fashion. However, dynamic imaging based on GRIN lens has not been studied extensively. Here, this paper presented a fluorescence endoscopic imaging system based on GRiN lenses using one-photon and two-photon excitation. GRIN lenses with 1.15 mm diameter and 7.65 mm length were used in the system. The images were acquired by a compact laser scanning imaging system with a resonant galvo-mirror system to scan the laser beam and a photomultiplier tube （PMT） to detect fluorescence signals. Experimental results showed that this system using two-photon excitation could implement dynamic fluorescence microendoscopic imaging and monitor the movement of blood flow beneath the skin in anesthetized mice while producing images with higher contrast and signal to noise ratio （SNR） than those using one photon excitation. It would be a useful tool for studying biological processes of small animals or plants in vivo.
文摘In this paper, a polymer spherical symmetry GRIN sphere lens were prepared by the suspension-diffusion-copolymerization(SDC) technique, selecting methyl methacrylate(MMA) as monomer M1 and acrylic 2,2,2-trifluoroethyl ester(3FEA) as M2. The radial distribution of refractive index of the lens was measured by the shearing interference method, which demonstrated that the quadratic refractive-index distribution was formed in the sphere lens, and its Δn=0.019.
文摘The beams of 980nm high-power LDs are analyzed, and the reasons that aspect ratio of LD beams is high are explained. It is certified by the test that cylindrical lens can efficiently compress the perpendicular divergence angle of the beam. Some typical and popular lensed fibers were compared and analyzed according to coupling characteristics. The factors which affect the coupling efficiency and tolerance of the wedged-shaped GRIN tipped lensed fiber are pointed out, and some methods to reduce the coupling loss of the lensed fibers are proposed finally.
文摘Fllowing the derivation of equations for ray propagation in anisotropic medium, the equations for determinining the ray path featuring progressively increasing and decreasing distribution of index of refraction are presented’ With computer the actual ray path can be trced and positions of both observation and image points can be quantitatively indicated for direct perceiving tbe mirage formation. At the end a discussion of the mirage observation zone is attached.
基金supported by the National Natural Science Foundation of China(31871054 and 31371112)the Intramural Research Program of the National Institute on Drug Abuse,NIH,USA
文摘The complex spatial and temporal organization of neural activity in the brain is important for informationprocessing that guides behavior. Hence, revealing the realtime neural dynamics in freely-moving animals is fundamental to elucidating brain function. Miniature fluorescence microscopes have been developed to fulfil this requirement. With the help of GRadient INdex(GRIN)lenses that relay optical images from deep brain regions to the surface, investigators can visualize neural activity during behavioral tasks in freely-moving animals. However, the application of GRIN lenses to deep brain imaging is severely limited by their availability. Here, we describe a protocol for GRIN lens coating that ensures successful long-term intravital imaging with commercially-available GRIN lenses.
