Simulation of the photoionization of nonmetal crystals by few-cycle femtosecond laser pulses

Gruzdev, Vitali E.; Sergaeva, Olga

doi:10.1117/1.oe.61.2.021006

Cited by 2 publications

(3 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Among them, we should mention the two that stand out. First is the need of proper implementation of the few-cycle photoionization model [78]. This work can potentially result in the development of a novel type of dynamic simulations for the few-cycle laser propagation coupled to highly non-equilibrium time-dependent material response.…”

Section: Discussionmentioning

confidence: 99%

“…Third, the cycle-averaged approach for modeling of the photoionization assumes slow variations of pulse-envelope compared to field oscillations at the center frequency of laser-pulse spectrum [51,77]. With reduction of pulse duration towards few optical cycle, this requirement may be violated, and some corrections to the Keldysh-type model are required [77,78]. However, implementation of those corrections into the FDTD simulation meets extra challenges since they depend on carrier-envelope phase that is well defined within one cycle around the moment of peaking laser-pulse electric field [78].…”

Section: Ionizationmentioning

confidence: 99%

“…With reduction of pulse duration towards few optical cycle, this requirement may be violated, and some corrections to the Keldysh-type model are required [77,78]. However, implementation of those corrections into the FDTD simulation meets extra challenges since they depend on carrier-envelope phase that is well defined within one cycle around the moment of peaking laser-pulse electric field [78]. Correspondingly, that parameter cannot be evaluated by the FDTD approach at the time moments prior to the laser-pulse peak.…”

Section: Ionizationmentioning

confidence: 99%

See 2 more Smart Citations

Ultrafast Laser Material Damage Simulation—A New Look at an Old Problem

et al. 2022

View full text Add to dashboard Cite

The chirped pulse amplification technique has enabled the generation of pulses of a few femtosecond duration with peak powers multi-Tera and Peta–Watt in the near infrared. Its implementation to realize even shorter pulse duration, higher energy, and higher repetition rate laser systems relies on overcoming the limitations imposed by laser damage of critical components. In particular, the laser damage of coatings in the amplifiers and in post-compression optics have become a bottleneck. The robustness of optical coatings is typically evaluated numerically through steady-state simulations of electric field enhancement in multilayer stacks. However, this approach cannot capture crucial characteristics of femtosecond laser induced damage (LID), as it only considers the geometry of the multilayer stack and the optical properties of the materials composing the stack. This approach neglects that in the interaction of an ultrashort pulse and the materials there is plasma generation and associated material modifications. Here, we present a numerical approach to estimate the LID threshold of dielectric multilayer coatings based on strong field electronic dynamics. In this dynamic scheme, the electric field propagation, photoionization, impact ionization, and electron heating are incorporated through a finite-difference time-domain algorithm. We applied our method to simulate the LID threshold of bulk fused silica, and of multilayer dielectric mirrors and gratings. The results are then compared with experimental measurements. The salient aspects of our model, such as the implementation of the Keldysh photoionization model, the impact ionization model, the electron collision model for ‘low’-temperature, dense plasma, and the LID threshold criterion for few-cycle pulses are discussed.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Ionizationmentioning

confidence: 99%

Section: Ionizationmentioning

confidence: 99%

See 1 more Smart Citation

Ultrafast Laser Material Damage Simulation—A New Look at an Old Problem

et al. 2022

View full text Add to dashboard Cite

show abstract

High-order (N = 4–6) multiphoton absorption and mid-infrared Kerr nonlinearity in GaP, ZnSe, GaSe, and ZGP crystals

et al. 2022

View full text Add to dashboard Cite

We report a study of high-order multiphoton absorption, nonlinear refraction, and their anisotropy in four notable mid-infrared χ(2) crystals: GaP, ZnSe, GaSe, and ZGP using femtosecond pulses at 2.35 μm with peak intensity in excess of 200 GW/cm2. We found that the nonlinear absorption obeys a perturbation model with multiphoton absorption (MPA) orders from N = 4–6, in agreement with the bandgaps of the crystals. A study of the role of free carrier absorption, performed by changing the pulse duration from 30 to 70 fs while maintaining a constant peak intensity, showed that, at our intensity levels, free carriers generated during the MPA process absorb much more strongly than would be expected from their known linear absorption cross section. Possible mechanisms for this anomalous behavior are high-field effects, such as intravalley scattering in the conduction band and absorption to higher lying bands. Nonlinear refractive indices were measured using (i) closed aperture Z-scan and (ii) spectral broadening due to self-phase modulation, both methods agreeing with each other.

show abstract

Simulation of the photoionization of nonmetal crystals by few-cycle femtosecond laser pulses

Cited by 2 publications

References 0 publications

Ultrafast Laser Material Damage Simulation—A New Look at an Old Problem

Ultrafast Laser Material Damage Simulation—A New Look at an Old Problem

High-order (N = 4–6) multiphoton absorption and mid-infrared Kerr nonlinearity in GaP, ZnSe, GaSe, and ZGP crystals

Contact Info

Product

Resources

About