scholarly journals Chirped-pulse oscillators for the generation of high-energy femtosecond laser pulses

2005 ◽  
Vol 23 (2) ◽  
pp. 113-116 ◽  
Author(s):  
ALEXANDER FUERBACH ◽  
A. FERNANDEZ ◽  
A. APOLONSKI ◽  
T. FUJI ◽  
F. KRAUSZ
Keyword(s):  
Repetition Rate ◽  
Laser Cavity ◽  
Laser Pulses ◽  
High Energy ◽  
Femtosecond Laser Pulses ◽  
Group Delay Dispersion ◽  
Picosecond Pulses ◽  
Chirped Pulse ◽  
Novel Approach ◽  
Extended Cavity

This paper reports on a novel approach for producing high energy femtosecond pulses without external amplification. The so-called chirped-pulse oscillator (CPO) concept is based on an extended-cavity oscillator, operating at small net positive intracavity group delay dispersion (GDD), over a broad spectral range by the use of chirped multilayer mirrors. The resultant chirped picosecond pulses are compressed by a dispersive delay line external to the laser cavity. Utilizing this technique, sub-30 fs pulses with an energy exceeding 200 nJ at a repetition rate of 11 MHz were produced. The demonstrated peak power in excess of 5 MW is the highest ever achieved from a cw-pumped laser and is expected to be scaleable to tens of megawatts by increasing the pump power and/or decreasing the repetition rate. The demonstrated source allows micromachining of any materials under relaxed focusing conditions.

scholarly journals Femtosecond Laser Pulses Amplification in Crystals

Crystals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 347
Author(s):  
Dabu
Keyword(s):  
Femtosecond Laser ◽  
Laser Pulses ◽  
High Energy ◽  
Femtosecond Laser Pulses ◽  
Phase Matching ◽  
Chirped Pulse ◽  
Nonlinear Crystals ◽  
Pulse Amplification ◽  
Chirped Pulse Amplification ◽  
Laser Crystals

This paper describes techniques for high-energy laser pulse amplification in multi-PW femtosecond laser pulses. Femtosecond laser pulses can be generated and amplified in laser media with a broad emission spectral bandwidth, like Ti:sapphire crystals. By chirped pulse amplification (CPA) techniques, hundred-Joule amplified laser pulses can be obtained. Multi-PW peak-power femtosecond pulses are generated after recompression of amplified chirped laser pulses. The characteristics and problems of large bandwidth laser pulses amplification in Ti:sapphire crystals are discussed. An alternative technique, based on optical parametric chirped pulse amplification (OPCPA) in nonlinear crystals, is presented. Phase-matching conditions for broad bandwidth parametric amplification in nonlinear crystals are inferred. Ultra-broad phase matching bandwidth of more than 100 nm, able to support the amplification of sub-10 fs laser pulses, are demonstrated in nonlinear crystals, such as Beta Barium Borate (BBO), Potassium Dideuterium Phosphate (DKDP), and Lithium Triborate (LBO). The advantages and drawbacks of CPA amplification in laser crystals and OPCPA in nonlinear crystals are discussed. A hybrid amplification method, which combines low-medium energy OPCPA in nonlinear crystals with high energy CPA in large aperture laser crystals, is described. This technique is currently used for the development of 10-PW laser systems, with sub-20 fs pulse duration and more than 1012 intensity contrast of output femtosecond pulses.

Optical breakdown and filamentation of femtosecond laser pulses propagating in air at a kHz repetition rate

2004 ◽  
Vol 13 (3) ◽  
pp. 359-363 ◽  
Author(s):  
Duan Zuo-Liang ◽  
Chen Jian-Ping ◽  
Li Ru-Xin ◽  
Lin Li-Huang ◽  
Xu Zhi-Zhan
Keyword(s):  
Femtosecond Laser ◽  
Repetition Rate ◽  
Optical Breakdown ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses

Wavelength tunable, high energy femtosecond laser pulses directly generated from large-mode-area photonic crystal fiber

2012 ◽  
Vol 285 (10-11) ◽  
pp. 2715-2718 ◽  
Author(s):  
Chi Zhang ◽  
Yu-ying Zhang ◽  
Ming-lie Hu ◽  
Si-jia Wang ◽  
You-jian Song ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Femtosecond Laser ◽  
Photonic Crystal Fiber ◽  
Laser Pulses ◽  
High Energy ◽  
Femtosecond Laser Pulses ◽  
Large Mode Area ◽  
Crystal Fiber ◽  
Wavelength Tunable ◽  
Mode Area

scholarly journals Effects of oblique incidence and colliding pulses on laser-driven proton acceleration from relativistically transparent ultrathin targets

2020 ◽  
Vol 86 (5) ◽  
Author(s):  
J. Ferri ◽  
E. Siminos ◽  
L. Gremillet ◽  
T. Fülöp
Keyword(s):  
Oblique Incidence ◽  
Laser Pulses ◽  
High Energy ◽  
Femtosecond Laser Pulses ◽  
Reference Case ◽  
Proton Acceleration ◽  
Ion Energy ◽  
High Energies ◽  
Proton Charge ◽  
Induced Transparency

The use of ultrathin solid foils offers optimal conditions for accelerating protons to high energies from laser–matter interactions. When the target is thin enough that relativistic self-induced transparency sets in, all of the target electrons get heated to high energies by the laser, which maximizes the accelerating electric field and therefore the final ion energy. In this work, we first investigate how ion acceleration by ultraintense femtosecond laser pulses in transparent CH $_2$ solid foils is modified when turning from normal to oblique ( $45^\circ$ ) incidence. Due to stronger electron heating, we find that higher proton energies can be obtained at oblique incidence but in thinner optimum targets. We then show that proton acceleration can be further improved by splitting the laser pulse into two half-pulses focused at opposite incidence angles. An increase by ${\sim }30\,\%$ in the maximum proton energy and by a factor of ${\sim }4$ in the high-energy proton charge is reported compared to the reference case of a single normally incident pulse.

scholarly journals High-Repetition-Rate Femtosecond Laser Processing of Acrylic Intra-Ocular Lenses

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 242 ◽  
Author(s):  
Daniel Sola ◽  
Rafael Cases
Keyword(s):  
Femtosecond Laser ◽  
Repetition Rate ◽  
Laser Processing ◽  
Refractive Index Change ◽  
Laser Pulses ◽  
Processing Parameters ◽  
High Repetition Rate ◽  
Femtosecond Laser Pulses ◽  
Periodic Patterns ◽  
High Repetition

The study of laser processing of acrylic intra-ocular lenses (IOL) by using femtosecond laser pulses delivered at high-repetition rate is presented in this work. An ultra-compact air-cooled femtosecond diode laser (HighQ2-SHG, Spectra-Physics) delivering 250 fs laser pulses at the fixed wavelength of 520 nm with a repetition rate of 63 MHz was used to process the samples. Laser inscription of linear periodic patterns on the surface and inside the acrylic substrates was studied as a function of the processing parameters as well as the optical absorption characteristics of the sample. Scanning Electron Microscopy (SEM) Energy Dispersive X-ray Spectroscopy (EDX), and micro-Raman Spectroscopy were used to evaluate the compositional and microstructural changes induced by the laser radiation in the processed areas. Diffractive characterization was used to assess 1st-order efficiency and the refractive index change.

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