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arXiv · 1702.04338

Beyond the perturbative description of the nonlinear optical response of low-index materials

Orad Reshef·Enno Giese·M. Zahirul Alam·Israel De Leon·Jeremy Upham·Robert W. Boyd
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Abstract

We show that standard approximations in nonlinear optics are violated for situations involving a small value of the linear refractive index. Consequently, the conventional equation for the intensity-dependent refractive index, $n(I) = n_0 + n_2 I$, becomes inapplicable in epsilon-near-zero and low-index media, even in the presence of only third-order effects. For the particular case of indium tin oxide, we find that the $χ^{(3)}$, $χ^{(5)}$ and $χ^{(7)}$ contributions to refraction eclipse the linear term; thus, the nonlinear response can no longer be interpreted as a perturbation in these materials. Although the response is non-perturbative, we find no evidence that the power series expansion of the material polarization diverges.

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Orad Reshef, Enno Giese, M. Zahirul Alam, Israel De Leon, Jeremy Upham, Robert W. Boyd. 2017-07-15. Beyond the perturbative description of the nonlinear optical response of low-index materials. https://doi.org/10.1364/ol.42.003225

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