Polarization conversion in cubic Raman crystals.
Nonlinear conversion of unpolarized beams to lower frequencies is generally inefficient in c(2)materials, as it is challenging to achieve phase-matching for input ordinary and extraordinary beams simultaneously in the normal dispersion regime. Here, we show that cubic Raman crystals having doubly and triply degenerate (E and F type) modes provide a method for efficient nonlinear frequency downconversion of an unpolarized beam and yield a linearly polarized output state. Using Mueller calculus, optimal crystal directions for such polarization conversion are determined. Using diamond, an example of an F-class Raman crystal, we have verified that such conversion is possible with near quantum-defect-limited slope efficiency and a linear polarization contrast of more than 23.9 dB.
MQ Photonics Research Centre, Department of Physics and Astronomy Faculty of Science and Engineering, Macquarie University Sydney New South Wales 2109 Australia.
Aaron
A
McKay
MQ Photonics Research Centre, Department of Physics and Astronomy Faculty of Science and Engineering, Macquarie University Sydney New South Wales 2109 Australia.|Defence Science and Technology Group, Edinburgh, South Australia 5111, Australia.
Alexander
A
Sabella
MQ Photonics Research Centre, Department of Physics and Astronomy Faculty of Science and Engineering, Macquarie University Sydney New South Wales 2109 Australia.
Richard P
RP
Mildren