The potential of optical parametric oscillators (OPOs) as versatile tools for an extensive range of applications is widely appreciated.
The arrival of new nonlinear materials, which are structured so as to have a periodic variation in non-linearity, have had a dramatic effect on nonlinear optical devices. The work in the OPO group draws on the world leading fabrication capabilities for these materials at the ORC (eg periodically-poled lithium niobate, PPLN, PPKTP, PPRTA) and explores the exciting new device possibilities. These include optical harmonic generators, optical parametric oscillators and amplifiers.
Current application areas include the use of OPOs as ultrafast, pulse-shaped, tunable mid-IR sources for coherent control of chemical reactions.
PhD Projects:
Supervisor: Prof D P Shepherd
Co-Supervisor: Prof D J Richardson, Dr S Alam
We will develop compact and robust fibre-laser-pumped mid-infrared parametric sources, working in the picosecond regime, for the generation of 2-12 µm supercontinua (SC) in ChG fibres for molecular fingerprint spectroscopy. The pump source will be based on a simple fibre-coupled, gain-switched, diode laser operating at ~2µm, spliced to a thulium-doped fibre amplifier chain to deliver average powers of ~10W.
The OPOs, based on orientation-patterned GaAs (OP-GaAs), will provide tunable output from 2.5 to 7µm. This flexibility will allow optimisation of the power and wavelength for SC generation in the fingerprint regime in a variety of fibre geometries.
The chalcogenide SC fibres can be tapered to enhance nonlinearity and to engineer the zero-dispersion wavelength.
The final SC will have ~100mW average powers and will span the 2-12 µm spectral region. The source will be able to address a substantial number of sensing applications in several distinct areas from environmental monitoring to medical diagnosis.