Formation of in-volume nanogratings with sub-100 nm periods in glass by femtosecond laser irradiation

TL;DR

This paper investigates the formation of sub-100 nm nanogratings in glass using femtosecond laser irradiation, combining experimental observations with theoretical simulations to understand the morphological evolution and mechanisms involved.

Contribution

It introduces a new mechanism explaining nanograting formation with periods smaller than those predicted by existing nanoplasmonic models, supported by experimental and simulation data.

Findings

Nanogratings with sub-100 nm periods are formed in glass.

Constructive interference of scattered light shortens nanograting periods.

The proposed mechanism explains formation beyond traditional nanoplasmonic predictions.

Abstract

We present direct experimental observation of the morphological evolution during the formation of nanogratings with sub-100-nm periods with the increasing number of pulses. Theoretical simulation shows that the constructive interference of the scattering light from original nanoplanes will create an intensity maximum located between the two adjacent nanoplanes, resulting in shortening of the nanograting period by half. The proposed mechanism enables explaining the formation of nanogratings with periods beyond that predicted by the nanoplasmonic model.