Measurement of the self-induced waveguide of a solitonlike optical beam in a nematic liquid crystal

Abstract

Using phase-measurement interferometry, we observe the waveguide induced by a solitonlike optical beam sustained by the molecular reorientation-induced optical nonlinearity of a nematic liquid crystal in planar configuration. Our purpose in the study is to characterize the nonlocality of the optical response of nematic liquid crystals. A good agreement is obtained between the experiment and a full ͑2+1͒-dimensional numerical simulation of the nonlinear optical beam propagation in the cell.

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

“…Our results establish a good quantitative agreement between experimental data and the modified SMM [2], as recently shown in [13]. Finally, the results from our group have been experimentally validated by several groups [14][15][16][17][18][19][20][21][22][23].…”

Soliton-assisted random lasing in optically-pumped liquid crystals

“…The latter response provides a low-power mechanism for nonlinear optics [19] and light localization into self-confined lightbeams, the so-called "nematicons" [20]. Nematicons are bright spatial solitons (solitary waves) which are stable in two transverse dimensions due to the nonlocal response associated with the elastic intermolecular links in the liquid state [21,22]; they support graded-index waveguides able to confine additional (incoherent) signals/beams of different wavelengths as well as powers and profiles [23][24][25][26][27][28][29][30], are robust against refractive index perturbations [31][32][33][34][35] and collisional interactions [36][37][38]. Aided by nematicons, reorientational and electronic nonlinear responses, characterized by distinct time-and power-scales, can synergystically be combined [39,40].…”

Observation of out-coupling of a nematicon

“…Due to the molecular reorientation under the influence of a linearly polarized optical electric field, the refractive index is higher where the optical intensity is higher. This leads to a focusing non linear effect that can compensate for the spreading of the beam occurring during propagation because of natural diffraction [7]. In this way, it becomes possible to propagate beams with practically invariant intensity profile, these entities are called spatial solitons and nematicons if we are dealing with nematic liquid crystals.…”

“…To the best of our knowledge, in all the reported experiments on nonlinear waveguiding in liquid crystals, the beam propagation in the cell is observed either via the light scattered by the liquid crystal [4][5][6][7][8][9][10] or via indirect observation by visualization of the self-induced waveguide [7,13]. In these measurements, the light beam (or the material properties) can only be observed in the plane parallel to the glass surfaces, while no information is available along the thickness of the cell.…”

“…In this way we are able to look at the beam itself at the output of the cell in order to gather some information about the behaviour of the beam along the thickness of the cell. Since the beam power reduces significantly along the propagation distance [7], the length of the cell along the propagation distance has to be small enough, in the order of a few millimetres. The cutting of narrow glass plates is done with a diamond saw, because the glass facets should be very smooth.…”