Ultrafast excitation of conduction-band electrons by high-intensity ultrashort laser pulses in band-gap solids: Vinogradov equation versus Drude model

Sergaeva, Olga; Gruzdev, Vitali E.; Austin, Drake; Chowdhury, Enam

doi:10.1364/josab.35.002895

Cited by 6 publications

(5 citation statements)

References 57 publications

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“…The weak variations of refractive index during a 200-fs laser pulse 10 signals that the laser-generated electron-hole plasma is substantially transparent. This could occur, for example, if the plasma is far from equilibrium 43,44 . Therefore, a reasonable criterion for LID threshold by the ultrashort laser pulses should consider the electron density required for ultrafast melting rather than the critical plasma density.…”

Section: Resultsmentioning

confidence: 99%

“…The weak variations of refractive index during a 200-fs laser pulse 10 signals that the laser-generated electron-hole plasma is substantially transparent. This could occur if the plasma is, for example, far from equilibrium 59,60 . This hypothesis is further supported by estimations of the energy of laser-generated conduction-band electrons (Table 2) that suggest the electron-particle collision time is of the order of few hundreds of femtoseconds 52 .…”

Section: Discussionmentioning

confidence: 99%

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Single-Shot Multi-Stage Damage and Ablation of Silicon by Femtosecond Mid-infrared Laser Pulses

Werner¹,

Gruzdev²,

Talisa³

et al. 2019

Sci Rep

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Although ultrafast laser materials processing has advanced at a breakneck pace over the last two decades, most applications have been developed with laser pulses at near-IR or visible wavelengths. Recent progress in mid-infrared (MIR) femtosecond laser source development may create novel capabilities for material processing. This is because, at high intensities required for such processing, wavelength tuning to longer wavelengths opens the pathway to a special regime of laser-solid interactions. Under these conditions, due to the λ2 scaling, the ponderomotive energy of laser-driven electrons may significantly exceed photon energy, band gap and electron affinity and can dominantly drive absorption, resulting in a paradigm shift in the traditional concepts of ultrafast laser-solid interactions. Irreversible high-intensity ultrafast MIR laser-solid interactions are of primary interest in this connection, but they have not been systematically studied so far. To address this fundamental gap, we performed a detailed experimental investigation of high-intensity ultrafast modifications of silicon by single femtosecond MIR pulses (λ = 2.7–4.2 μm). Ultrafast melting, interaction with silicon-oxide surface layer, and ablation of the oxide and crystal surfaces were ex-situ characterized by scanning electron, atomic-force, and transmission electron microscopy combined with focused ion-beam milling, electron diffractometry, and μ-Raman spectroscopy. Laser induced damage and ablation thresholds were measured as functions of laser wavelength. The traditional theoretical models did not reproduce the wavelength scaling of the damage thresholds. To address the disagreement, we discuss possible novel pathways of energy deposition driven by the ponderomotive energy and field effects characteristic of the MIR wavelength regime.

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Section: Resultsmentioning

confidence: 99%

“…The weak variations of refractive index during a 200-fs laser pulse 10 signals that the laser-generated electron-hole plasma is substantially transparent. This could occur if the plasma is, for example, far from equilibrium 59,60 . This hypothesis is further supported by estimations of the energy of laser-generated conduction-band electrons (Table 2) that suggest the electron-particle collision time is of the order of few hundreds of femtoseconds 52 .…”

Section: Discussionmentioning

confidence: 99%

Single-Shot Multi-Stage Damage and Ablation of Silicon by Femtosecond Mid-infrared Laser Pulses

Werner¹,

Gruzdev²,

Talisa³

et al. 2019

Sci Rep

Self Cite

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“…For the lineouts, the input pulse power was chosen such that Figure 3(a) clearly shows two distinct pump power regimes in spectral broadening of the harmonics, despite a relative lack of broadening dynamics in the fundamental. Potential reasons for the lack of broadening dynamics in the fundamental include: energy losses from linear absorption, free carrier absorption [27], depletion from harmonics generation, or inaccuracy of cr P due to lack of MIR data [12]. In perturbative harmonic generation with perfect phase matching, the ideal FWHM bandwidth of generated harmonics ( ( ) n λ Δ where n is the harmonic order) is related to the FWHM of the fundamental ( [28].…”

Section: Numerical Modeling Of Optical Filamentationmentioning

confidence: 99%

Ultrafast mid-infrared high harmonic and supercontinuum generation with n₂ characterization in zinc selenide

et al. 2019

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“…Thus, measurement of characteristic time for the coherent processes is essential for both fundamental and applied research. The dephasing time T 2 in crystals at room temperature has been deemed that it is comparable to typical optical period of the MIR laser pulse [6,42]. It implies that this characteristic time can be exposed by the MIR laser pulses.…”

Section: S(l) Qmentioning

confidence: 99%

Probing the dephasing time of crystals via spectral properties of high-order harmonic generation

2019

Phys. Rev. A

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Coherent time is a characteristic time in the extreme nonlinear optics regime and thus generally introduced as the dephasing time in the simulations of the solid-state high-harmonic generation. This characteristic time linked with the coherent decay of quantum trajectory controls the emergence of the spectral splittings in the high harmonic spectroscopy, which can been attributed to the temporal interference between two adjacent harmonic emission channels. To reproduce the harmonic peaks and spectral splittings, a temporal two-slit interference model in the momentum space is introduced. In addition, mechanisms of spectral splitting provide a state-of-the-art avenue to probe the characteristic elapse between electron and hole. Based on the subfemtosecond resolution of the spectral interference opening and closing zones in the wavelength-dependent high-order harmonic spectra, we also propose an alternative scheme to probe the dephasing time of crystals by the feasible laser pulses in present experimental setups.

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Ultrafast excitation of conduction-band electrons by high-intensity ultrashort laser pulses in band-gap solids: Vinogradov equation versus Drude model

Cited by 6 publications

References 57 publications

Single-Shot Multi-Stage Damage and Ablation of Silicon by Femtosecond Mid-infrared Laser Pulses

Single-Shot Multi-Stage Damage and Ablation of Silicon by Femtosecond Mid-infrared Laser Pulses

Ultrafast mid-infrared high harmonic and supercontinuum generation with n₂ characterization in zinc selenide

Probing the dephasing time of crystals via spectral properties of high-order harmonic generation

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Ultrafast excitation of conduction-band electrons by high-intensity ultrashort laser pulses in band-gap solids: Vinogradov equation versus Drude model

Cited by 6 publications

References 57 publications

Single-Shot Multi-Stage Damage and Ablation of Silicon by Femtosecond Mid-infrared Laser Pulses

Single-Shot Multi-Stage Damage and Ablation of Silicon by Femtosecond Mid-infrared Laser Pulses

Ultrafast mid-infrared high harmonic and supercontinuum generation with n2 characterization in zinc selenide

Probing the dephasing time of crystals via spectral properties of high-order harmonic generation

Contact Info

Product

Resources

About

Ultrafast mid-infrared high harmonic and supercontinuum generation with n₂ characterization in zinc selenide