Observation of Temporal Solitons in Second-Harmonic Generation with Tilted Pulses

Families of Bragg-grating solitons in a cubic–quintic medium

“…In this case, the size of available samples is a few cm, hence the corresponding soliton's dispersion length must be very small, 1 cm, which cannot be provided for by the material's intrinsic dispersion, even if the soliton is very narrow, with the temporal width ∼ 100 fs. As was experimentally demonstrated in the above-mentioned works [2] and [3] (and proposed in the theoretical work [4]), the necessary strong dispersion can be generated by BG. A similar situation takes place in BG-carrying silica fibers, where very strong dispersion induced by BG makes it possible to generate solitons (supported by the usual Kerr nonlinearity) in a very short piece of fiber [5].…”

“…In some media, however, the intrinsic chromatic dispersion is too weak to support solitons in the temporal or spatiotemporal domain; then, much stronger artificial dispersion can be induced by means of a Bragg grating (BG) written on the sample. Notable examples are temporal [2] and spatiotemporal [3] solitons that were created in second-harmonic-generating crystals. In this case, the size of available samples is a few cm, hence the corresponding soliton's dispersion length must be very small, 1 cm, which cannot be provided for by the material's intrinsic dispersion, even if the soliton is very narrow, with the temporal width ∼ 100 fs.…”

Embedded solitons: a new type of solitary wave

“…Recent progress with the observation of the temporal (gap) solitons in second-harmonic generating optical media [30] suggests that the ESs may well be observable too. It is also noteworthy that, in fact, a weak cubic nonlinearity is sufficient to generate ESs, which is what one expects to be present in a typical material.…”

Quadratic solitons with gain and loss

“…Such conditions can be met with existing high-quality materials; thus, spatial solitons have been observed with picosecond pulses in planar waveguides made of lithium niobate (LiNbO cut for type I phase-matching SHG pumped at m [4], in up-and down-conversion SHG schemes in bulk potassium titanyl phosphate (KTiOPO or KTP) cut for type II phasematching at m [5], [6] m [7], in quasi-phase-matched SHG in periodically poled LiNbO (PPLN) pumped at m [8], and in OPA in lithium triborate (LiB O operated for type I noncritical phase-matching at the signal-idler band m [9]. Pulse narrowing consistent with temporal soliton formation was observed recently using achromatic phasematching techniques in -barium borate -BaB O or BBO) pumped with 200-fs pulses for SHG at m [10]. In this paper, we address the possibility to form quadratic solitons in new settings, unexplored wavelength bands, and novel materials where the different waves forming the solitons experience significant absorption losses or linear gain depending on the wavelength band to which they belong.…”