# Quasi-Phase-Matching in Chiral Materials

## TL;DR

This paper demonstrates quasi-phase-matching in chiral materials using alternating enantiomer stacks, enabling frequency conversion based on chirality rather than polar order, with experimental validation via second-harmonic generation.

## Contribution

It introduces a novel approach to quasi-phase-matching utilizing chiral structures, expanding the possibilities for frequency converters based on chirality.

## Key findings

- Successful second-harmonic generation from chiral stacks
- Chirality-based quasi-phase-matching demonstrated experimentally
- Potential for new frequency converter designs

## Abstract

The second-order nonlinear optical coefficients associated with chirality differ in sign for the two mirror-image forms (enantiomers) of a chiral material. Structures comprised of alternating stacks of the enantiomers can therefore be used for quasi-phase-matched frequency conversion, as we demonstrate here by second-harmonic generation from Langmuir-Blodgett films of a helicenebisquinone. Such structures could lead to new types of frequency converters in which both the second-order nonlinear response and quasi-phase-matching arise from the chirality of a material rather than its polar order. PACS numbers: 42.65.Ky, 42.70.Nq, 78.66.Qn

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Source: https://tomesphere.com/paper/1905.06015