Division of aperture to reduce the focus spot size

2000 ◽  
Author(s):  
Liangyu Li ◽  
Changchun Li ◽  
Huajun Yang ◽  
Yinzhu Li ◽  
Yaping Dai ◽  
...  
Keyword(s):  
Spot Size ◽  
Focus Spot ◽  
Focus Spot Size

scholarly journals Photonic Jet-Shaped Optical Fiber Tips versus Lensed Fibers

Photonics ◽  
2021 ◽  
Vol 8 (9) ◽  
pp. 373
Author(s):  
Djamila Bouaziz ◽  
Grégoire Chabrol ◽  
Assia Guessoum ◽  
Nacer-Eddine Demagh ◽  
Sylvain Lecler
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Single Mode ◽  
Spot Size ◽  
Base Diameter ◽  
Core Diameter ◽  
Focus Spot ◽  
Photonic Jet ◽  
Focus Spot Size ◽  
Focusing Properties

Shaped optical fiber tips have recently attracted a lot of interest for photonic jet light focusing due to their easy manipulation to scan a sample. However, lensed optical fibers are not new. This study analyzes how fiber tip parameters can be used to control focusing properties. Our study shows that the configurations to generate a photonic jet (PJ) can clearly be distinguished from more classical-lensed fibers focusing. PJ is a highly concentrated, propagative light beam, with a full width at half maximum (FWHM) that can be lower than the diffraction limit. According to the simulations, the PJs are obtained when light is coupled in the guide fundamental mode and when the base diameter of the microlens is close to the core diameter. For single mode fibers or fibers with a low number of modes, long tips with a relatively sharp shape achieve PJ with smaller widths. On the contrary, when the base diameter of the microlens is larger than the fiber core, the focus point tends to move away from the external surface of the fiber and has a larger width. In other words, the optical system (fiber/microlens) behaves in this case like a classical-lensed fiber with a larger focus spot size. The results of this study can be used as guidelines for the tailored fabrication of shaped optical fiber tips according to the targeted application.

Speckle pattern sequential extraction metric for estimating the focus spot size on a remote diffuse target

2017 ◽  
Vol 56 (32) ◽  
pp. 8941 ◽  
Author(s):  
Zhan Yu ◽  
Yuanyang Li ◽  
Lisheng Liu ◽  
Jin Guo ◽  
Tingfeng Wang ◽  
...  
Keyword(s):  
Sequential Extraction ◽  
Speckle Pattern ◽  
Spot Size ◽  
Focus Spot ◽  
Focus Spot Size

scholarly journals Research on fiber coupling technology of kilowatt laser diode by single emitters

2018 ◽  
Vol 189 ◽  
pp. 11008 ◽  
Author(s):  
Wenbin Qin ◽  
Jing Li ◽  
Lei Yao ◽  
Youqiang Liu ◽  
Yuntao Qiu ◽  
...  
Keyword(s):  
Diode Laser ◽  
Coupling Efficiency ◽  
Processing System ◽  
Spot Size ◽  
Theoretical Research ◽  
Fiber Coupling ◽  
Output Laser Power ◽  
Fiber Taper ◽  
Output Laser ◽  
Focus Spot Size

This paper proposes a program that combine the laser of single-emitters by using fiber combiner, what’s more, we designed and developed a multiple single emitters diode laser module of full optical fiber. We used ZEMAX software to simulate and optimize the influence of fiber coupling efficiency by the location of cylindrical lens and fiber, finally, we developed 8W fiber coupling single emitter diode laser, the wavelength is 915nm, fiber diameter is 105/125μm, NA0.15. This article also carried on the theoretical research of N×1 fiber combiner, and based on Vytran GPX glass processing system, we fabricated the 19×1fiber combiner by TFB technique, combined 19 105/122μm, NA0.15 fibers to a 400/440μm, NA0.22 fiber, has realized 150W laser output, with fiber combining efficiency more than 96%. In the end, 8*400um fibers are synthesized through a fiber taper. The output laser power after fiber taper reached 1453W, with the focus spot size is 2.25mm*1.1mm and power density reached 6×104W/cm2.

Design and performance of bending-magnet beamline BL02B at the SSRF

2019 ◽  
Vol 26 (2) ◽  
pp. 543-550 ◽  
Author(s):  
Xiangyu Meng ◽  
Zhi Guo ◽  
Yong Wang ◽  
Hui Zhang ◽  
Yong Han ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
High Performance ◽  
Ambient Pressure ◽  
Spot Size ◽  
Resolving Power ◽  
Photon Flux ◽  
Shanghai Synchrotron Radiation Facility ◽  
Excitation Spectra ◽  
And Performance ◽  
Focus Spot Size

The BL02B bending-magnet beamline at the Shanghai Synchrotron Radiation Facility (SSRF) has been constructed and is now operational for ambient-pressure photoelectron spectroscopy (APPES) and photon-in/photon-out spectroscopy (PIPOS) experimental use. Optical optimization was implemented for realization of high performance, e.g. photon flux, energy-resolving power and focus spot size. X-ray photoelectron spectroscopy experiments show that the energy range extends from 40 to 2000 eV. Argon, nitrogen and neon gas core-shell excitation spectra indicate energy-resolving powers of over 1.4 × 104 @ 244 eV, 1.0 × 104 @ 401 eV and 7.0 × 103 @ 867 eV, respectively. The measured photon flux is 1.3 × 1011 photons s−1 @ E/ΔE = 3700 at 244 eV at the expected sample position, for the SSRF electron energy of 3.5 GeV and electron current of 240 mA. The spot sizes are 177 µm × 23 µm and 150 µm × 46 µm at the APPES and PIPOS samples, respectively.

scholarly journals Mechanical Properties of Fibre Laser Welded AZ31B Sheets and their Dependence on the Spot-Size

2015 ◽  
Vol 828-829 ◽  
pp. 298-304
Author(s):  
Stefan Riekehr ◽  
Riccardo Ravasi ◽  
Josephin Enz ◽  
Volker Ventzke ◽  
Nikolai Kashaev
Keyword(s):  
Laser Beam ◽  
Laser System ◽  
Base Material ◽  
Spot Size ◽  
Fibre Laser ◽  
Beam Power ◽  
Spot Diameter ◽  
Laser Beam Power ◽  
Focus Spot ◽  
Weld Area

In the present work the mechanical behaviour of laser beam welded AZ31B alloy was studied, by changing systematically the spot size of the used fibre laser system between 200 µm and 1000 µm at different power levels between 2 kW and 8 kW. Maximum welding velocities with respect to imperfections were determined. The characterization of the obtained welds - in terms of Vickers hardness, UTS, Af and weld width, resp. weld area - was correlated with the micro-texture in dependence of the different Focus Spot Diameters and Laser Beam Power levels as well as the resulting cooling rates. Highest UTS of 94% of the base material was achieved with 200 µm Focus Spot Diameter and Laser Beam Power of 4 kW at welding velocity of 100 mm/s. By increasing the Focus Spot Diameter to 600 µm, the tensile strength was reduced to 86 % of the actual strength of the base material.

Remarks on the application of backscattered electron imaging (BEI) to the scanning electron microscopy (SEM) of biological structures

1983 ◽  
Vol 41 ◽  
pp. 484-487
Author(s):  
Etienne de Harven
Keyword(s):  
High Resolution ◽  
Incident Beam ◽  
Spot Size ◽  
Primary Electron ◽  
Critical Point Drying ◽  
Cell Shapes ◽  
High Resolution Images ◽  
Backscattered Electron ◽  
Electron Imaging ◽  
Scanning Electron

Biological ultrastructures have been extensively studied with the scanning electron microscope (SEM) for the past 12 years mainly because this instrument offers accurate and reproducible high resolution images of cell shapes, provided the cells are dried in ways which will spare them the damage which would be caused by air drying. This can be achieved by several techniques among which the critical point drying technique of T. Anderson has been, by far, the most reproducibly successful. Many biologists, however, have been interpreting SEM micrographs in terms of an exclusive secondary electron imaging (SEI) process in which the resolution is primarily limited by the spot size of the primary incident beam. in fact, this is not the case since it appears that high resolution, even on uncoated samples, is probably compromised by the emission of secondary electrons of much more complex origin.When an incident primary electron beam interacts with the surface of most biological samples, a large percentage of the electrons penetrate below the surface of the exposed cells.

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