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Ultrafast sub-30-fs all-optical switching based on gallium phosphide
Gustavo Grinblat1,2, Michael P Nielsen1,3, Paul Dichtl1
1The Blackett Laboratory, Department of Physics, Imperial College London, London SW7 2AZ, UK.
Science Advances
|June 20, 2019
Summary
Gallium phosphide (GaP) films enable ultrafast optical switching. This material achieves high transmission modulation speeds up to 20 THz due to its strong optical nonlinearity and negligible losses.
Area of Science:
- Materials Science
- Optics
- Photonics
Background:
- Gallium phosphide (GaP) exhibits strong optical nonlinearity.
- It has negligible optical losses in the visible and near-infrared spectrum.
- Ultrafast all-optical switching requires materials with high nonlinearities and low losses.
Purpose of the Study:
- To demonstrate the potential of GaP films for ultrafast all-optical switching.
- To quantify the transmission modulation capabilities of GaP.
- To investigate the underlying nonlinear mechanisms in GaP.
Main Methods:
- Fabrication of GaP films.
- Characterization of nonlinear optical properties using Z-scan measurements.
- Nonlinear optical simulations to model transmission modulation.
Main Results:
- Achieved sub-30-femtosecond (fs) transmission modulation up to ~70% in GaP films.
- Demonstrated modulation in the 600- to 1000-nm wavelength range.
- Identified the optical Kerr effect and two-photon absorption as primary mechanisms, with no free-carrier contribution.
Conclusions:
- GaP is a promising material for ultrafast all-optical switching applications.
- The material supports modulation speeds up to 20 THz.
- Its performance is attributed to strong optical nonlinearity and absence of linear absorption.
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