PNO: A Promising Deep-UV Nonlinear Optical Material with Extremely High Second Harmonic Generation Effect

TL;DR

This paper predicts a new deep-UV nonlinear optical material, PNO, with an extremely high second harmonic generation effect and good stability, making it promising for optical applications.

Contribution

The study introduces PNO, a thermodynamically stable deep-UV NLO material with the strongest SHG effect among known deep-UV materials, based on first-principles predictions.

Findings

PNO has the strongest SHG coefficient among deep-UV materials.

PNO exhibits good mechanical and thermal stability.

PNO is a promising candidate for deep-UV nonlinear optics.

Abstract

In this work, the polar tetrahedron [PN$_2$O$_2$] was revealed as a new deep-ultraviolet (deep-UV) nonlinear optically active unit. Accordingly, a thermodynamically stable compound (PNO) consisting of the polar [PN$_2$O$_2$] units was predicted and suggested as a promising candidate of deep-UV nonlinear optical (NLO) material. Compared with other deep-UV materials known to date, PNO possesses the strongest second harmonic generation (SHG) coefficient (about 6 times that of KH$_2$PO$_4$ (KDP)). Moreover, its three-dimensional connectivity endows it with good mechanical and thermal properties. Therefore, PNO should be a new option for non-$\pi$-conjugated deep-UV NLO materials.