Ultrafast Optical Response of a High-Reflectivity GaAs/AlAs Bragg Mirror

TL;DR

This paper investigates the ultrafast optical response of a GaAs/AlAs Bragg mirror, demonstrating significant transmission changes on picosecond timescales for potential use in ultrafast optical switching.

Contribution

It presents experimental results and a theoretical design for a high-reflectivity, ultrafast switchable mirror using nonlinear optical effects in GaAs/AlAs structures.

Findings

Transmission increased by a factor of 27 experimentally.

Theoretical switching ratios up to 2200 predicted.

Potential applications in quantum optics and optical communication.

Abstract

The ultrafast response of a high-reflectivity GaAs/AlAs Bragg mirror to optical pumping is investigated for all-optical switching applications. Both Kerr and free carrier nonlinearities are induced with 100 fs, 780 nm pulses with a fluence of 0.64 kJ/m^2 and 0.8 kJ/m^2. The absolute transmission of the mirror at 931 nm increases by a factor of 27 from 0.0024% to 0.065% on a picosecond timescale. These results demonstrate the potential for a high-reflectivity ultrafast switchable mirror for quantum optics and optical communication applications. A design is proposed for a structure to be pumped below the bandgaps of the semiconductor mirror materials. Theoretical calculations on this structure show switching ratios up to 2200 corresponding to switching from 0.017% to 37.4% transmission.