Optical parametric oscillator

Laboratory setup of an OPO

An optical parametric oscillator (abbr. OPO , English optical parametric oscillator ) used in laser technology consists essentially of an optically non-linear crystal , e.g. B. Beta-Barium Borate (BBO), in an optical resonator . The crystal generates radiation of two wavelengths, so-called signal and idler radiation , from an irradiated pump wave via the nonlinear three-wave interaction . Either the generated idler radiation or the signal radiation is partially fed back via a mirror. This increases the energy of the resonant wave with each passage through the crystal. In this way, parametric amplification can take place with significant conversion efficiency, since the process no longer has to start from the parametric noise.

The conservation of energy shows that the sum of the quantum energies of the signal and idler radiation generated corresponds to the quantum energy of the pump radiation and thus the same for the frequencies . For efficient frequency conversion, however, not only the conservation of energy, but also the phase adjustment condition must be met. ${\displaystyle f_{P}=f_{S}+f_{I}}$

This method can be used to generate laser radiation whose wavelength is outside the wavelengths of available active laser media.

Furthermore, the sum or difference frequency (corresponding to the sum or difference of the respective quantum energies) of two radiated light waves can be generated with optically non-linear crystals.

The first tunable optical parametric oscillators were developed in 1965 at Bell Laboratories by Joseph A. Giordmaine and Robert C. Miller .

literature

• Georg A. Reider: Photonics - An introduction to the basics. Springer-Verlag, Vienna 2005, ISBN 3-211-21901-3 (in particular chapter 8)

Web links

• Optical Parametric Oscillators in the Encyclopedia of Laser Physics and Technology (engl.)