Search query: A Deep Ultraviolet Mode-locked Laser Based on a neural network

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abstract: Deep ultraviolet lasers based on the phenomenon of mode locking have been used widely in many areas in recent years, for example, in semiconductors, the environment and biomedicine. In the development of a mode locked deep ultraviolet laser, one of the most important aspects is to optimize the multiple parameters of the complex system. Traditional optimization methods require experimenters with more optimization experience, which limits the wide application of the lasers. In this study, we optimize the deep ultraviolet mode locked laser system using an online neural network to solve this problem. The neural network helps us control the position of the crystal, the length of the cavity, the position of the focusing lens and the temperature of the frequency doubling crystal. We generate a deep ultraviolet mode locked laser with a power of 18 mW and a spectral center at 205 nm. This result is greatly improved compared to previous results with the same pump power. This technology provides a universal solution to multiparameter problems in the optimization of lasers.
author_names: Haoyuan Lu

Hao Xu

Jianye Zhao

Dong Hou
title: A Deep Ultraviolet Mode locked Laser Based on a Neural Network
venue: Scientific Reports
year: 2020

abstract: Both observational and perturbational technologies are essential for advancing the understanding of brain function and dysfunction. But while observational techniques have greatly advanced in the last century, techniques for perturbation that are matched to the speed and heterogeneity of neural systems have lagged behind. The technology of optogenetics represents a step toward addressing this disparity. Reliable and targetable single component tools (which encompass both light sensation and effector function within a single protein) have enabled versatile new classes of investigation in the study of neural systems. Here we provide a primer on the application of optogenetics in neuroscience, focusing on the single component tools and highlighting important problems, challenges, and technical considerations.
author_names: Ofer Yizhar

Lief E Fenno

Thomas J Davidson

Murtaza Z Mogri

Karl Deisseroth
title: Optogenetics in Neural Systems
venue: Neuron
year: 2011

abstract: With few exceptions biological tissues strongly scatter light, making high resolution deep imaging impossible for traditional including confocal fluorescence microscopy. Nonlinear optical microscopy, in particular two photon excited fluorescence microscopy, has overcome this limitation, providing large depth penetration mainly because even multiply scattered signal photons can be assigned to their origin as the result of localized nonlinear signal generation. Two photon microscopy thus allows cellular imaging several hundred microns deep in various organs of living animals. Here we review fundamental concepts of nonlinear microscopy and discuss conditions relevant for achieving large imaging depths in intact tissue.
author_names: Fritjof Helmchen

Winfried Denk
title: Deep tissue two photon microscopy
venue: Nature Methods
year: 2005

abstract: A compact, electrically driven light source integrated on silicon is a key component for large scale integration of electronic and photonic integrated circuits. Here we demonstrate electrically injected continuous wave lasing in InP based microdisk lasers coupled to a sub micron silicon wire waveguide, fabricated through heterogeneous integration of InP on silicon on insulator (SOI) The InP based microdisk has a diameter of 7.5 mum and a thickness of 1 mum. A tunnel junction was incorporated to efficiently contact the p side of the pn junction. The laser emits at 1.6 mum, with a threshold current as low as 0.5 mA under continuous wave operation at room temperature, and a threshold voltage of 1.65 V. The SOI coupled laser slope efficiency was estimated to be 30 muW/mA, with a maximum unidirectional output power of 10 muW.
author_names: Joris Van Campenhout

Pedro Rojo Romeo

P Regreny

Christian Seassal

Dries van Thourhout

Steven Verstuyft

Lea Di Cioccio

Jean-Marc Fedeli

Chrystelle Lagahe

Roel Baets
title: Electrically pumped InP based microdisk lasers integrated with a nanophotonic silicon on insulator waveguide circuit.
venue: Optics express
year: 2007

abstract: Molecular excitation by the simultaneous absorption of two photons provides intrinsic three dimensional resolution in laser scanning fluorescence microscopy. The excitation of fluorophores having single photon absorption in the ultraviolet with a stream of strongly focused subpicosecond pulses of red laser light has made possible fluorescence images of living cells and other microscopic objects. The fluorescence emission increased quadratically with the excitation intensity so that fluorescence and photo bleaching were confined to the vicinity of the focal plane as expected for cooperative two photon excitation. This technique also provides unprecedented capabilities for three dimensional, spatially resolved photochemistry, particularly photolytic release of caged effector molecules.
author_names: Winfried Denk

James H Strickler

Watt W Webb
title: Two photon laser scanning fluorescence microscopy.
venue: Science
year: 1990

abstract: Author(s) Vogel, Alfred; Venugopalan, Vasan Abstract: The mechanisms of pulsed laser ablation of biological tissues were studied. The transiently empty space created between the fiber tip and the tissue surface improved the optical transmission to the target and thus increased the ablation efficiency. It was found that the structure and morphology also affect the energy transport among tissue constituents.
author_names: Alfred Vogel

Vasan Venugopalan
title: Mechanisms of pulsed laser ablation of biological tissues.
venue: Chemical reviews
year: 2003

abstract: In the following, the first results on ultraviolet laser desorption (UVLD) of bioorganic compounds in the mass range above 10000 daltons are reported. Strong molecular ion signals were registered by use of an organic matrix with strong absorption at the wavelength used for controlled energy deposition and soft desorption (7)
author_names: Michael Karas

F Hillenkamp
title: Laser desorption ionization of proteins with molecular masses exceeding 10,000 daltons.
venue: Analytical chemistry
year: 1988

abstract: Solid State Laser Engineering is written from an industrialperspective and discusses in detail the characteristics, design, construction and practical problems of solid statelasers. Emphasis is placed on engineering and practicalconsiderations, with a phenomenological treatment usingmodelsbeing preferred to abstract mathematical derivations.This new edition has been updated and revised to includeimportant developments, concepts and technologies that haveemerged since the publication of the first edition.
author_names: Walter Koechner
title: Solid State Laser Engineering
year: 1976

abstract: RATIONALE AND OBJECTIVES To examine a statistical validation method based on the spatial overlap between two sets of segmentations of the same anatomy. MATERIALS AND METHODS The Dice similarity coefficient (DSC) was used as a statistical validation metric to evaluate the performance of both the reproducibility of manual segmentations and the spatial overlap accuracy of automated probabilistic fractional segmentation of MR images, illustrated on two clinical examples. Example 1: 10 consecutive cases of prostate brachytherapy patients underwent both preoperative 1.5T and intraoperative 0.5T MR imaging. For each case, 5 repeated manual segmentations of the prostate peripheral zone were performed separately on preoperative and on intraoperative images. Example 2: A semi automated probabilistic fractional segmentation algorithm was applied to MR imaging of 9 cases with 3 types of brain tumors. DSC values were computed and logit transformed values were compared in the mean with the analysis of variance (ANOVA) RESULTS Example 1: The mean DSCs of 0.883 (range, 0.876 0.893) with 1.5T preoperative MRI and 0.838 (range, 0.819 0.852) with 0.5T intraoperative MRI (P .001) were within and at the margin of the range of good reproducibility, respectively. Example 2: Wide ranges of DSC were observed in brain tumor segmentations: Meningiomas (0.519 0.893) astrocytomas (0.487 0.972) and other mixed gliomas (0.490 0.899) CONCLUSION The DSC value is a simple and useful summary measure of spatial overlap, which can be applied to studies of reproducibility and accuracy in image segmentation. We observed generally satisfactory but variable validation results in two clinical applications. This metric may be adapted for similar validation tasks.
author_names: Kelly H Zou

S Warfield

Aditya Bharatha

Clare M Tempany

Michael R Kaus

Steven Haker

William M Wells

Ferenc A Jolesz

Ron Kikinis
title: Statistical validation of image segmentation quality based on a spatial overlap index.
venue: Academic radiology
year: 2004

author_names: R E Stenkamp Prof

D C Teller Prof

Korrespondenzadresse Prof
title: Crystal structure of rhodopsin: a G protein coupled receptor. Palczewski K,(1) kumasaka T, hori T, behnke CA, motoshima H, fox BA, trong IL, teller DC, okada T, stenkamp RE, yamamoto M, miyano M. Science 2000;289:739 745
venue: American journal of ophthalmology
year: 2000