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When a fundamental beam propagates perpendicular to the optical axis of a nonlinear crystal with randomly distributed ferroelectric domains showing inverted sign of 2nd order nonlinearity (χ2), the generated second harmonic (SH) signal is spatially distributed in a plane, perpendicular to the optical axis [1]. Because the angular distribution of the SH intensity in this plane depends on the particular...
Amplification of vortex beam in flash-lamp-pumped Nd:YAG amplifiers has been demonstrated. A maximum output pulse energy up to 995mJ has been achieved at 10 Hz in a 10 ns pulse, corresponding to an amplification efficiency of 295%. Second-harmonic generation of the amplified vortex output was performed using nonlinear a KD.P crystal. Maximum second-harmonic energy of 470mJ was generated. The joule...
YAl3(BO3)4 crystal enables the highest UV power of 1.8 MW and shortest pulse of 118 ps with power conversion efficiency of 37 % at 266 nm by using LBO crystal and Nd:YAG/Cr:YAG microchip laser.
The second harmonic signal at the output of an optically poled fiber was studied as a function of the input fundamental frequency power and polarization state. For an injected average power of 3 mW at 1064 nm, the measured output power at 532 nm was 10 μW. The second harmonic intensity profile was a bright green ring even if the pump was injected in the fundamental HE11 mode: we believe that the second...
When the chalcogenide-tellurite hybrid optical fiber is pumped by an optical parametric oscillator with the pump wavelength from 1700 to 3000 nm, widely tunable second-harmonic generation (SHG) from 850 nm to 1502 nm is obtained.
We report on a continuously tunable fiber laser emitting between 1020 nm and 1070 nm with peak power in excess of 4 MW. This source is optimally adapted for frequency conversion in the visible by means of Four wave mixing.
Silica nanowires with high nonlinearities are attractive for a variety of applications such as continuum generation and new light sources. In particular, a growing interest was shown in using these nanowires for second harmonic generation (SHG) and third harmonic generation (THG) [1-3]. However, conversion efficiencies remain low, and new methods to improve this conversion are still required. In this...
Due to their strong modal confinement, optical microfibres (OMs) provide an excellent opportunity for studying nonlinear effects and in particular intermodally phase matched second (SHG) and third (THG) harmonic generation [1-3] with predicted efficiencies up to 10−1 over several cm in an ideal uniform silica OM for both cases. Experimentally however, fabricating the required phase matching diameter...
To date, the development of coherent ultra-broadband (i.e., with a bandwidth exceeding a full octave of the spectrum) laser sources and associated frequency combs has spanned the spectral regions from the near-infrared (NIR) to the ultra-violet (UV). For extending the generation of coherent supercontinuum (SC) sources and frequency combs into the mid-infrared (MIR), the natural candidate is silicon...
With the availability of intense and stable femtosecond sources, the modern focus of ultrafast science has been shifting toward precise coherent control of light-matter interaction on the fundamental time scales [1]. Such control necessarily entails the ability to generate phase-stable symmetry-broken synthetic optical waveforms. The most direct approach to accomplish this is to superpose a fundamental...
Quasi-phasematching (QPM) has been utilized for a wide variety of nonlinear-optical devices, for applications such as ultrafast optics and quantum optics [1, 2]. A key advantage of this technology is its high degree of engineerability, enabled by the freedom in fabricating QPM gratings with a wide range of periods and lengths. This enables, for example, pulse compression via second-harmonic generation,...
Numerical simulations of harmonic wave and supercontinuum generation in optical devices with both quadratic and third-order nonlinearity by means of the generalized nonlinear envelope equation approach are validated and analysed.
Nonlinear chirped pulse amplification at high average power and supercontinuum generation are demonstrated in bandgap fibres. A hollow-core fibre is proposed as a host for nonlinear frequency conversion in gas.
We study theoretically the second harmonic generation in a nonlinear quadratic crystal with random distribution of ferroelectric domains. We show that the specific features of disordered domain structure greatly affect the emission pattern of the generated harmonics. This phenomenon can be used to characterize the degree of disorder in nonlinear photonic structures.
The relative and absolute phases of femtosecond 1.03-μm pump, 1.55-μm signal and 3.09-μm idler pulses are stabilized paving the way for the generation of optimized driver-waveforms for higher-order-harmonic generation and electron impulsive momentum transfer.
Using noncollinear difference-frequency four-wave-mixing between the fundamental and third-harmonic of an amplified Ti:sapphire laser in argon, sub-50-fs VUV pulses with more than 2.5-µJ at 160-nm are generated.
Efficient continuous-wave sum-frequency generation with a bandwidth exceeding 60 nm was obtained in AlGaAs Bragg-reflection waveguide for type-II nonlinear interaction. Normalized conversion efficiency of 317 %W−1cm−2 was estimated in a device with 2.2 mm length.
Third harmonic generation in fibre nanotapers by intermodal coupling is experimentally characterized. UV radiation is generated from a pulsed 1064 nm laser in a 3 cm taper of 492 nm diameter.
A numerical simulation study is carried out to understand the optimal design of single photon frequency up-converter that achieves a large suppression of background noise without compromising photon frequency up-conversion efficiency. We show that by introducing a controlled amount of phase mismatch to the parasitic process of second-harmonic generation of the pump, background noise photons due to...
Widely tunable phase-locked THz transients with electric and magnetic fields exceeding 100 MV/cm are generated by a novel table-top laser. These pulses are able to drive non-perturbative optical nonlinearities by electric and magnetic coupling.
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