Fast carrier dynamics in GaAs photonic crystals near the material band edge at room temperature

TL;DR

This study measures ultrafast carrier decay in GaAs photonic crystal cavities at room temperature, revealing rapid dynamics near the band edge with implications for photonic device performance.

Contribution

It provides the first experimental measurement of 6 ps carrier decay times in GaAs photonic crystals near the band edge at room temperature.

Findings

Carrier decay time is approximately 6 ps.

Photoexcitation causes a significant blue-shift in cavity resonance.

Theoretical models align with experimental free carrier effects.

Abstract

We measure fast carrier decay rates (6 ps) in GaAs photonic crystal cavities with resonances near the GaAs bandgap energy at room temperature using a pump-probe measurement. Carriers generated via photoexcitation using an above-band femtosecond pulse cause a substantial blue-shift in the cavity peak. The experimental results are compared to theoretical models based on free carrier effects near the GaAs band edge. The probe transmission is modified for an estimated above-band pump energy of 4.2 fJ absorbed in the GaAs slab.