scholarly journals Simulation Study on Optically Designed Refractive Beam Expander for Nd: YAG Laser Harmonics for 7 Km Detection Range

2014 ◽  
Vol 11 (2) ◽  
pp. 742-747
Author(s):  
Baghdad Science Journal
Keyword(s):  
Harmonic Generation ◽  
Simulation Study ◽  
Second Harmonic ◽  
Spot Size ◽  
Expansion Ratio ◽  
Detection Range ◽  
Yag Laser ◽  
Third Harmonic ◽  
Received Power ◽  
Beam Expander

The simulation study has been conducted for the harmonics of Nd: YAG laser, namely the second harmonic generation SHG, the third harmonic generation THG, and the fourth harmonic generation FHG. Determination of beam expander's expansion ratio for specific wavelength and given detection range is the key in beam expander design for determining minimum laser spot size at the target. Knowing optimum expansion ratio decreases receiving unit dimensions and increases its performance efficiency. Simulation of the above mentioned parameters is conducted for the two types of refractive beam expander, Keplerian and Galilean. Ideal refractive indices for the lenses are chosen adequately for Nd: YAG laser harmonics wavelengths, so that increasing transmission of laser beam, consequently the received power to the detector for practical convenience.

High-power ultrafast thin-disk multipass amplifiers for efficient laser-based manufacturing

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Marwan Abdou Ahmed ◽  
Christoph Roecker ◽  
André Loescher ◽  
Florian Bienert ◽  
Daniel Holder ◽  
...  
Keyword(s):  
Harmonic Generation ◽  
State Of The Art ◽  
Second Harmonic ◽  
Average Power ◽  
Polycrystalline Diamond ◽  
Third Harmonic Generation ◽  
Thin Disk ◽  
Ultrafast Laser ◽  
Third Harmonic ◽  
Laser Systems

Abstract Thin-disk multipass amplifiers represent one of the most powerful approaches to scale the average and peak powers of ultrafast laser systems. The present paper presents the amplification of picosecond and femtosecond pulses to average powers exceeding 2 and 1 kW, respectively. Second-harmonic generation in lithium-triborate crystals with powers higher than 1.4 kW and 400 W at a wavelength of 515 nm with picosecond and femtosecond pulse durations, respectively, are also reported. Furthermore, third-harmonic generation was demonstrated with output powers exceeding 250 W at a wavelength of 343 nm. Finally, processing of silicon, metals, and polycrystalline diamond with fs pulses at an average power of 1 kW is presented to demonstrate removal rates that are improved by orders of magnitude as compared to state-of-the-art techniques.

scholarly journals Multiphoton Microscopy for Ophthalmic Imaging

2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Emily A. Gibson ◽  
Omid Masihzadeh ◽  
Tim C. Lei ◽  
David A. Ammar ◽  
Malik Y. Kahook
Keyword(s):  
Harmonic Generation ◽  
Second Harmonic ◽  
Imaging Techniques ◽  
Multiphoton Microscopy ◽  
Tissue Imaging ◽  
Third Harmonic ◽  
Two Photon ◽  
Disease Mechanisms ◽  
Ophthalmic Imaging ◽  
Anti Stokes

We review multiphoton microscopy (MPM) including two-photon autofluorescence (2PAF), second harmonic generation (SHG), third harmonic generation (THG), fluorescence lifetime (FLIM), and coherent anti-Stokes Raman Scattering (CARS) with relevance to clinical applications in ophthalmology. The different imaging modalities are discussed highlighting the particular strength that each has for functional tissue imaging. MPM is compared with current clinical ophthalmological imaging techniques such as reflectance confocal microscopy, optical coherence tomography, and fluorescence imaging. In addition, we discuss the future prospects for MPM in disease detection and clinical monitoring of disease progression, understanding fundamental disease mechanisms, and real-time monitoring of drug delivery.

scholarly journals Protein-crystal detection with a compact multimodal multiphoton microscope

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Qing-di Cheng ◽  
Hsiang-Yu Chung ◽  
Robin Schubert ◽  
Shih-Hsuan Chia ◽  
Sven Falke ◽  
...  
Keyword(s):  
Data Collection ◽  
Harmonic Generation ◽  
Diffraction Data ◽  
Second Harmonic ◽  
High Sensitivity ◽  
Protein Crystal ◽  
Third Harmonic ◽  
Increasing Demand ◽  
Biomolecular Crystallography ◽  
Nano Crystal

Abstract There is an increasing demand for rapid, effective methods to identify and detect protein micro- and nano-crystal suspensions for serial diffraction data collection at X-ray free-electron lasers or high-intensity micro-focus synchrotron radiation sources. Here, we demonstrate a compact multimodal, multiphoton microscope, driven by a fiber-based ultrafast laser, enabling excitation wavelengths at 775 nm and 1300 nm for nonlinear optical imaging, which simultaneously records second-harmonic generation, third-harmonic generation and three-photon excited ultraviolet fluorescence to identify and detect protein crystals with high sensitivity. The instrument serves as a valuable and important tool supporting sample scoring and sample optimization in biomolecular crystallography, which we hope will increase the capabilities and productivity of serial diffraction data collection in the future.

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