The ultrafast optical parametric oscillator group carries out research on both the development of these coherent light sources and their applications.
Optical parametric oscillators (OPOs) perform very much like standard laser sources, with an optical gain medium and an optical resonator. However, in this case the gain medium is not based, for example, on atomic transitions, but instead on parametric frequency conversion in a nonlinear crystal. Modern nonlinear crystals, such as periodically-poled LiNbO3 (PPLN), offer designer microstructures that can be used to phase-match a particular nonlinear interaction. OPOs therefore offer some unusual and highly advantageous properties such as:
1. Broad wavelength tunability, much greater than the standard solid-state laser option _ the Ti:sapphire laser.
2. Access to important wavelength regions, such as the mid-IR.
3. No heat input into the crystal from the basic gain process, in contrast to even the most efficient rare-earth-ions, such as Yb3+, thereby offering potential for power scaling.
4. A variety of output formats - continuous wave, pulsed, or ultrafast, depending upon the pump laser.
Our research aims to explore such possibilities and find new applications for these extraordinary devices.