Spatial optical solitons in highly nonlocal media

Abstract

We theoretically investigate the propagation of bright spatial solitary waves in highly nonlocal media possessing radial symmetry in a three-dimensional cylindrical geometry. Focusing on a thermal nonlinearity, modeled by a Poisson equation, we show how the profile of the light-induced waveguide strongly depends on the extension of the nonlinear medium in the propagation direction as compared to the beamwidth. We demonstrate that self-trapped beams undergo oscillations in size, either periodically or aperiodically, depending on the input waist and power. The-usually neglected-role of the longitudinal nonlocality as well as the detrimental effect of absorptive losses are addressed.

Comment on “Spatial optical solitons in highly nonlocal media”

“…This discrepancy stems from the role of the boundary conditions." They cited this result again in [5] (this time as "discrepancy is due to the singularity (at the origin) of the response function used here") and again, as their own. But this crucial result was published before in [7] and [10].…”

“…Because of the simplicity of the theory, they coined the term accessible solitons (ASs) for these optical spatial solitary waves.An early experimental observation of accessible solitons was reported in [2, 3]: "We believe that most of the observed spatial optical solitons in nematic liquid crystals (NLCs) are indeed accessible solitons, inasmuch as NLC are highly nonlocal." The same authors have determined the basic beam evolution laws for highly nonlocal NLCs in [2,3], which are later elaborated in [4,5]. Equation (6) in [3] was used to interpret the experiments; the authors claimed good agreement between the data and model predictions.However, straightforward application of the AS approximation, even in nonlinear media with almost infinite range of nonlocality, inevitably leads to additional problems [2,3,6], because there exists no real physical medium without boundaries and without losses.…”

“…An early experimental observation of accessible solitons was reported in [2,3]: "We believe that most of the observed spatial optical solitons in nematic liquid crystals (NLCs) are indeed accessible solitons, inasmuch as NLC are highly nonlocal." The same authors have determined the basic beam evolution laws for highly nonlocal NLCs in [2,3], which are later elaborated in [4,5]. Equation (6) in [3] was used to interpret the experiments; the authors claimed good agreement between the data and model predictions.…”

“…Next, it remains unclear why authors omitted to cite accurate results for the beam width and the period of small oscillations presented in [7], although they wrote and published a comment [8] on that paper. Instead, in [4] they chose to cite the paper by Ouyang et al [12], and in [5] they cited themselves. However, the relevance of [12] to the problems at hand is indirect; it analyzes the approximate solutions of strongly nonlocal solitons.…”

Reply to “Comment on ‘Spatial optical solitons in highly nonlocal media”'

“…In doing so, we also tried to understand the limits of this approximation by direct comparison with experiments. Eventually, we thank Petrovic et al for spotting a wrong factor in [1], which we have amended in [61].…”