Slow Light Nanocoatings for Ultrashort Pulse Shaping

TL;DR

This paper demonstrates ultrathin nanostructured coatings that utilize slow light effects to control dispersion and compress ultrashort laser pulses, enabling improved pulse shaping for optical applications.

Contribution

The study introduces silicon nanopillar array coatings that tailor dispersion and compress femtosecond pulses, a novel approach for ultrashort pulse manipulation.

Findings

Coatings induce anomalous group delay dispersion around 800 nm.

Experimental demonstration of temporal pulse compression.

Performance characterized via white light interferometry.

Abstract

Transparent materials do not absorb light but have profound influence on the phase evolution of transmitted radiation. One consequence is chromatic dispersion, i.e., light of different frequencies travels at different velocities, causing ultrashort laser pulses to elongate in time while propagating. Here we experimentally demonstrate ultrathin nanostructured coatings that resolve this challenge: we tailor the dispersion of silicon nanopillar arrays such that they temporally reshape pulses upon transmission using slow light effects and act as ultrashort laser pulse compressors. The coatings induce anomalous group delay dispersion in the visible to near-infrared spectral region around 800 nm wavelength over an 80 nm bandwidth. We characterize the arrays' performance in the spectral domain via white light interferometry and directly demonstrate the temporal compression of femtosecond laser pulses. Applying these coatings to conventional optics renders them ultrashort pulse compatible and suitable for a wide range of applications.