Abstract
We show that manipulation and selection of optical patterns is possible by detuning the frequency of one of the two waves in counterpropagating photorefractive two-wave mixing with a feedback mirror. An analytical expression for the onset of modulational instability is derived for the general case of an arbitrary complex coupling constant, including a possible frequency shift of the generated sidebands. The influence of frequency detuning of the pump beams on the spatial scale of the resulting pattern and on the threshold value of the photorefractive coupling strength for modulational instability is investigated. The spatial scale and the frequency detuning of the generated sidebands were measured in an experiment using a photorefractive KNbO3 crystal. Comparison of theory and experiment show agreement for positive frequency detuning of the pump beams. For negative detuning we observe clamping of the spatial scale and no frequency shift of the sidebands. Possible explanations of this deviation between analytical results and experiment are discussed.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
More From: Journal of Optics B: Quantum and Semiclassical Optics
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.