Third harmonic generation in self-focused filaments in liquids

Abstract

Intense filaments of third harmonic generation have been observed in a variety of liquids when pumped by 1300 nm wavelength femtosecond light. The onset of third harmonic generation coincides with the threshold for self-focusing as deduced from n(2) measurements performed on the liquids using the z-scan technique. We have found self-phase modulation above the threshold leading to continuum generation at about 3 times threshold. In the third-harmonic regime, the third harmonic output power is independent of the input power. Our observations are consistent with those for similar processes in gases as described by a phase-locking model. The measured conversion efficiency was approximately 10(6).

Third- and fifth-harmonic generation in transparent solids with few-optical-cycle midinfrared pulses

“…To this end, generation of third, fifth [26][27][28], and seventh [29] harmonics by filamentation of midinfrared laser pulses in air was recently experimentally observed. Generation of low-order odd harmonics was also reported under various experimental settings in semiconductors [30], and in liquid [31,32] and solid-state [15,16,33] dielectric media.…”

In Situ Bioconjugation: Single Step Approach to Tailored Nanoparticle‐Bioconjugates by Ultrashort Pulsed Laser Ablation

“…These maxima can be explained by the self-focusing phenomena of intensive laser irradiation at 800 nm exceeding 8.9 MW in water. [26] The distance between the lens and the focus is shortened; therefore, a lower focal position is required for maximal laser intensity and ablation. Laser intensity above and below the focus is decreased due to broadening of the laser beam and shielding effects, respectively.…”

Enhancement of third-harmonic emission from femtosecond laser filament screened partially by a thin fiber

“…The TH emission is a fundamental process during the femtosecond laser filamentation, which has the potential applications in remote sensing and achieving high-intensity coherent UV light sources [1][2][3]. The dynamics of the copropagation of fundamental wave (FW) and TH have been investigated intensively under various conditions, such as different wavelengths, pulse durations, divergent angles, and focusing conditions [4][5][6][7][8][9][10][11][12][13][14][15].…”