Optical rectification by ratchet transport in an asymmetric grating

P Moroshkin,R Osgood,T Ochiai,J Xu

doi:10.1063/5.0062816

Abstract

We report on electron ratchet transport’s manifestation in the optical rectification (OR) of an asymmetric grating. The photon-drag enabled effect is magnified by asymmetric photon scatterings and the induced optical nonlinearity associated with the surface plasmon polariton (SPP) via its near-field and gradient intensifications. The measured OR efficiency is increased multi-fold, over the prior art, which is attributable to its operating in a higher-order diffraction and nonlinearity regime and to a minimized coupling loss to a potential SPP mode at the lower interface.

Highlights

The asymmetric profile of the grating leads to unequal reflections scitation.org/journal/adv of the positive and negative diffraction orders at θ = 0 and to a non-symmetric dependence on θ
D ≈ 2λLas favors higher diffraction orders. This can be seen in the gold-air grating surface plasmon polariton (SPP) mode wavelength dependence14 on the structural parameters
The other structural difference by design is in the thickness of the gold film. 100 nm was chosen in our case vs the 40 nm in Ref. 5

Summary

Introduction

The asymmetric profile of the grating leads to unequal reflections scitation.org/journal/adv of the positive and negative diffraction orders at θ = 0 and to a non-symmetric dependence on θ. The grating was designed to maximize the differences between the m = −1 and m = +1 diffraction orders for normal incident laser light of λLas = 808 nm, corresponding to a maximal momentum transfer to the electrons in the metal grating.

Results

Conclusion