Paving the way for third harmonic generation in hollow-core photonic bandgap fibers

TL;DR

This paper introduces two innovative silica-based hybrid photonic structures with dual bandgaps, enabling third harmonic generation and high-power laser delivery at two distinct wavelengths.

Contribution

The paper proposes novel hybrid photonic structures with two well-separated bandgaps suitable for third harmonic generation in hollow-core fibers.

Findings

Two hybrid structures with dual bandgaps are demonstrated.

Bandgaps have a ratio of approximately 3 between their central frequencies.

Designs enable efficient third harmonic generation and laser delivery at two wavelengths.

Abstract

We present two novel hybrid photonic structures made of silica that possess two well-separated frequency bandgaps. The addition of interstitial air holes in a precise location and size allows these bandgaps to open up with a ratio of ${\sim3}$ between their central frequencies at the air line ${ck_z/w=1}$, thus fulfilling the basic guidance condition for third harmonic generation in hollow-core fibers. In addition, these designs may serve as high-power laser delivery of two well-separated wavelengths, such as visible and near infrared.