Theoretical analysis of single-cycle self-compression of near infrared pulses using high-spatial modes in capillary fibers

Abstract

Soliton self-compression is demonstrated during the propagation of high spatial modes in hollow core fibers in the near-infrared spectral region, taking advantage of their negative dispersion response. We have found that there is always an optimum spatial mode to observe this phenomenon, compressing the pulses down to the single-cycle regime without needing any external compression device and with a consequent increase in the output peak power. Our result is relevant for any ultrashort laser application in which few- or single-cycle pulses are crucial.

Influence of the spatial confinement on the self-focusing of ultrashort pulses in hollow-core fibers

“…Taking into account that the anomalous dispersion response of the gas increases with the wavelength 34 , as shown in Table 2, one expects to observe a stronger self-compression process for the Yb-doped than for the Ti:Sa laser and, therefore, an earlier spatial collapse. This is exactly what can be observed when comparing Fig.…”

Spatiotemporal-dressed optical solitons in hollow-core capillaries

“…All the results presented here do not include any noise in the input beam, but we have checked that adding white noise to the phase of the input beam does not alter the dynamics. For more details on the simulation see [26,32]. The dynamics shown in Fig.…”

“…Nowadays there is an increasing interest in studying nonlinear effects in multi-mode (MM) fibers. The MM systems have the difficulty of showing a complex spatio-temporal evolution, but they present other nonlinear ingredients that could be interesting for a variety of effects, such as the super-continuum generation in MM HC-PCFs [20], the optical soliton formation or other spatio-temporal effects observed in graded-index MM optical fibers [21][22][23][24], the presence of vector soliton solutions on step-index MM optical fibers [25], or the self-compressed pulse generated using high-spatial modes in hollow-core capillaries (also called hollow-core fibers HCFs) [26], to mention just some examples. Moreover, the extraordinary control that can be achieved nowadays allows us to couple the light in a single high order mode of a hollow-core fibre [27,28], and also of a hollow-core photonic crystal fiber [29,30].…”

“…We will call it a spatiotemporal-dressed optical soliton. We have recently demonstrated that, although the higher spatial modes of the HCF (the HE 1m modes with m > 1) have non-negligible losses, they present anomalous dispersion response in the near infrared spectral region that could lead to the activation of self-compression processes [26]. Figure 1 shows the theoretical self-compression dynamics of the second excited spatial mode (HE 13 ) propagating in a 1 meter long HCF with 150 µm core radius (r F ) filled with 1 bar of argon.…”

High-energy pulse self-compression and ultraviolet generation through soliton dynamics in hollow capillary fibres

“…Theoretical suggestions of how to obtain soliton effects in HCF-which require nonlinearity and dispersion to act simultaneously within the fibre-have included the use of metal-coated HCF to reduce the loss [39], pumping in higherorder modes to increase u nm in Eq. 1 [40,41], or moving to longer wavelengths [42,43]. However, only numerical results on self-compression have been reported so far, with the rich variety of soliton-induced effects remaining unexplored, and no experiments performed to date.…”