Femtosecond Laser Pulses Operation in Crystal under High-Power Diode Pumping

2015 ◽  
Vol 1101 ◽  
pp. 169-172
Author(s):  
Brij Mohan Kumar Prasad ◽  
Amrit Bawankan

We report on a diode laser which is used to pump directly the crystal with a semiconductor saturable absorber allows passive mode locking for the generation of pulses with an average power along with the broadband light by focusing on ultrashort laser pulses into crystal tungstate. The nonuniformity can lead to the crystal and bonding failure. Also model the thermal and structural properties at the various tempeartures to observe the beam quality. Extends the generated spectrum from the infrared to ultraviolet through the visible region, it consists of discrete spatially separated sidebands.

Author(s):  
V. Pouget ◽  
E. Faraud ◽  
K. Shao ◽  
S. Jonathas ◽  
D. Horain ◽  
...  

Abstract This paper presents the use of pulsed laser stimulation with picosecond and femtosecond laser pulses. We first discuss the resolution improvement that can be expected when using ultrashort laser pulses. Two case studies are then presented to illustrate the possibilities of the pulsed laser photoelectric stimulation in picosecond single-photon and femtosecond two-photon modes.


Nanophotonics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3153-3159 ◽  
Author(s):  
Pablo Díaz-Núñez ◽  
Sabrina L. J. Thomä ◽  
Guillermo González-Rubio ◽  
Olivia Borrell-Grueiro ◽  
Roland P. M. Höller ◽  
...  

Abstract We report on the irradiation of gold rod–sphere assemblies with ultrashort laser pulses, producing structures that are very difficult to obtain by other methods. The optical response of these assemblies displays several peaks arising from the interaction of the plasmon modes of the individual particles, offering thus great flexibility to control the energy deposited on the individual particles. Judicious selection of the wavelength and fluence of the laser pulses allow fine control over the changes produced: the particles can be melted, welded and/or the organic links cleaved. In this way, it is possible to generate structures “à la carte” with a degree of control unmatched by other synthetic protocols. The method is exemplified with gold nanoparticles, but it can be easily implemented on particles composed of different metals, widening considerably the range of possibilities. The final structures are excellent candidates for surface-enhanced spectroscopies or plasmonic photothermal therapy as they have a very intense electric field located outside the structure, not in the gaps.


Author(s):  
L. Martín ◽  
J. Benlliure ◽  
D. Cortina-Gil ◽  
J. Peñas ◽  
C. Ruiz

We report the development of a stable high-average power X-ray source generated by the interaction of ultrashort laser pulses (35 fs, 1 mJ, 1 kHz) with a solid target in air. The achieved source stability, which is essential for the applications foreseen for these laser-driven plasma accelerators, is due to the combination of precise positioning of the target on focus and the development of a fast rotating target system able to ensure the refreshment of the material at every shot while minimizing positioning errors with respect to the focal spot. This vacuum-free laser-plasma X-ray source provides an average dose rate of 1.5 Sv/h at 30 cm and a repeatability better than 93% during more than 36 min of continuous operation per target.


Nanophotonics ◽  
2017 ◽  
Vol 6 (5) ◽  
pp. 743-763 ◽  
Author(s):  
Martin Ams ◽  
Peter Dekker ◽  
Simon Gross ◽  
Michael J. Withford

AbstractOptical waveguide Bragg gratings (WBGs) can be created in transparent materials using femtosecond laser pulses. The technique is conducted without the need for lithography, ion-beam fabrication methods, or clean room facilities. This paper reviews the field of ultrafast laser-inscribed WBGs since its inception, with a particular focus on fabrication techniques, WBG characteristics, WBG types, and WBG applications.


2001 ◽  
Author(s):  
C. H. Fan ◽  
J. Sun ◽  
J. P. Longtin

Abstract Optical breakdown by ultrashort laser pulses in dielectrics presents an efficient method to deposit laser energy into materials that otherwise exhibit minimal absorption at low laser intensities. During optical breakdown, a high density of free electrons is formed in the material, which dominates energy absorption, and, in turn, the material removal rate during ultrafast laser-material processing. Classical models assume spatially uniform electron population and constant laser intensity in the focal region, which results in a time-dependent expressions only, i.e., the rate equations, to predict electron evolution induced by nanosecond and picosecond pulses. For femtosecond pulses, however, the small spatial extent of the pulse requires that the pulse propagation be considered, which results in inhomogeneous plasma and localized electron formation during optical breakdown. In this work, a femtosecond breakdown model is combined with the classical rate equations to determine both time- and position-dependent electron density during femtosecond optical breakdown in water. The model exhibits good agreement when compared with experimental results. For other transparent or moderately absorbing dielectric media, the model also shows promise for determining the time- and position-dependent electron evolution induced by ultrashort laser pulses. Another interesting result is that the maximum electron density formed during femtosecond-laser-induced optical breakdown can exceed the conventional limit imposed by the plasma frequency.


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