Gaussian beam profile and single transverse mode emission from previously multimode gain-guided VCSEL using novel etch

2000 ◽  
Author(s):  
Loic M. A. Plouzennec ◽  
Laurence J. Sargent ◽  
Richard V. Penty ◽  
Ian H. White ◽  
Peter J. Heard ◽  
...  
Keyword(s):  
Gaussian Beam ◽  
Transverse Mode ◽  
Beam Profile

Effect of laser beam truncation (pinhole), (ordered) dithering, and jitter on residual smoothness after poly(methyl methacrylate) ablations, using a close-to-Gaussian beam profile

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Shwetabh Verma ◽  
Juergen Hesser ◽  
Samuel Arba-Mosquera
Keyword(s):  
Laser Beam ◽  
Methyl Methacrylate ◽  
Gaussian Beam ◽  
Low Cost ◽  
Random Noise ◽  
Beam Profile ◽  
Negatively Associated ◽  
Poly Methyl Methacrylate ◽  
The Impact ◽  
Ordered Dithering

Abstract Smoother surfaces after laser vision correction have been widely accepted as a factor for improving visual recovery regardless of the used technique (PRK, LASIK, or even SMILE). We tested the impact of laser beam truncation, dithering (expressing a continuous profile on a basis of lower resolution causing pixels to round up/down the number of pulses to be placed), and jitter (a controlled random noise (up to ±20 µm in either direction) added to the theoretical scanner positions) on residual smoothness after Poly(methyl methacrylate) (PMMA) ablations, using a close-to-Gaussian beam profile. A modified SCHWIND AMARIS system has been used providing a beam profile with the following characteristics: close-to-Gaussian beam profile with full width at half maximum (FWHM) of 540 µm, 1050 Hz. Laser parameters have been optimized following Invest. Ophthalmol. Vis. Sci., vol. 58, no. 4, pp. 2021–2037, 2017, the pulse energy has been optimized following Biomed. Opt. Express vol. 4, pp. 1422–1433, 2013. For the PMMA ablations, two configurations (with a 0.7 mm pinhole and 0.75 mJ and without pinhole and 0.9 mJ (for fluences of 329 mJ/cm2 and 317 mJ/cm2 and corneal spot volumes of 174 and 188 pl)) were considered, along with two types of lattices (with and without ordered dithering to select the optimum pulse positions), and two types of spot placement (with and without jitter). Real ablations on PMMA (ranging from −12D to +6D with and without astigmatism of up to 3D) completed the study setup. The effect of the 2 × 2 × 2 different configurations was analyzed based on the roughness in ablation estimated from the root mean square error in ablation. Truncation of the beam is negatively associated to a higher level of residual roughness; ordered dithering to select the optimum pulse positions is positively associated to a lower level of residual roughness; jitter is negatively associated to a higher level of residual roughness. The effect of dithering was the largest, followed by truncation, and jitter had the lowest impact on results. So that: Dithering approaches help to further minimize residual roughness after ablation; minimum (or no) truncation of the beam is essential to minimize residual roughness after ablation; and jitter shall be avoided to minimize residual roughness after ablation. The proposed model can be used for optimization of laser systems used for ablation processes at relatively low cost and would directly improve the quality of results. Minimum (or no) truncation of the beam is essential to minimize residual roughness after ablation. Ordered dithering without jitter helps to further minimize residual roughness after ablation. Other more complex dithering approaches may further contribute to minimize residual roughness after ablation.

Dynamic Multimode Analysis of High-Power Lasers with Super-Gaussian Beam Profile using Precombined Gaussian Modes

2010 ◽  
Author(s):  
Matthias Wohlmuth ◽  
Konrad Altmann ◽  
Michaël Hemmer ◽  
Mario Goehre ◽  
Christoph Pflaum ◽  
...  
Keyword(s):  
Gaussian Beam ◽  
High Power ◽  
Beam Profile ◽  
High Power Lasers

Increasing transverse stability of optical tweezers by using dual-Gaussian beam profile

2000 ◽  
Vol 9 (1) ◽  
pp. 65-68 ◽  
Author(s):  
Yao Xin-cheng ◽  
Li Zhao-lin ◽  
Cheng Bing-ying ◽  
Han Xue-hai ◽  
Zhang Dao-zhong
Keyword(s):  
Gaussian Beam ◽  
Optical Tweezers ◽  
Beam Profile ◽  
Transverse Stability

Shaping the beam profile of an elliptical Gaussian beam by an elliptical phase aperture

2013 ◽  
Vol 291 ◽  
pp. 31-37 ◽  
Author(s):  
Wei Wen ◽  
Gaofeng Wu ◽  
Kehui Song ◽  
Yiming Dong
Keyword(s):  
Gaussian Beam ◽  
Beam Profile

Characteristics of beam profile of Gaussian beam passing through an axicon

2004 ◽  
Vol 239 (4-6) ◽  
pp. 367-372 ◽  
Author(s):  
Ming Lei ◽  
Baoli Yao
Keyword(s):  
Gaussian Beam ◽  
Beam Profile

scholarly journals Beam Profile Characterisation of an Optoelectronic Silicon Lens-Integrated PIN-PD Emitter between 100 GHz and 1 THz

2021 ◽  
Vol 11 (2) ◽  
pp. 465
Author(s):  
Jessica Smith ◽  
Mira Naftaly ◽  
Simon Nellen ◽  
Björn Globisch
Keyword(s):  
Gaussian Beam ◽  
Beam Profile ◽  
Terahertz Communications ◽  
Silicon Lens ◽  
Terahertz Emitters

Knowledge of the beam profiles of terahertz emitters is required for the design of terahertz instruments and applications, and in particular for designing terahertz communications links. We report measurements of beam profiles of an optoelectronic silicon lens-integrated PIN-PD emitter at frequencies between 100 GHz and 1 THz and observe significant deviations from a Gaussian beam profile. The beam profiles were found to differ between the H-plane and the E-plane, and to vary strongly with the emitted frequency. Skewed profiles and irregular side-lobes were observed. Metrological aspects of beam profile measurements are discussed and addressed.

Numerical simulation of a Gaussian beam profile passing through a Kerr medium

2009 ◽  
Vol 9 (6) ◽  
pp. 1347-1350 ◽  
Author(s):  
E. Koushki ◽  
S.H. Mousavi ◽  
M.H. Majles Ara ◽  
A. Koushki
Keyword(s):  
Numerical Simulation ◽  
Gaussian Beam ◽  
Beam Profile ◽  
Kerr Medium
Sign in / Sign up

Export Citation Format

Share Document