Mainz 1997 – wissenschaftliches Programm
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MO: Molekülphysik
MO 8: Poster I: Photoelektronen, Photodissoziation, Cluster, Methoden
MO 8.31: Poster
Dienstag, 4. März 1997, 16:00–18:00, Poster
Optical phase conjugation in Rb vapour — •O.K. Andersen1,2, E. Louvergneaux2, M.J.J. Vrakking1, S. Stolte1, and D. Lenstra2 — 1Laser Centre, Chemistry, Vrije Universiteit, De Boelelaan 1083, 1081 HV Amsterdam, Netherlands — 2Theoretical Physics, Vrije Universiteit, De Boelelaan 1083, 1081 HV Amsterdam, Netherlands
We have performed studies of optical phase conjugation in Rb vapour. Experimentally, the phase conjugate signal is obtained by a nearly degenerate four wave mixing scheme with interacting beams derived from a Ti:Sapphire laser. The wavelength of the Ti:Sapphire laser is tuned close to a Rb transition line (780 nm) where strong nonlinear response can be observed. The maximum reflectivity obtained is 15%. In the theoretical study we are solving the equation of motion for the density matrix of a 3-level system interaction with 2 pump beams and a probe beam. From the calculated temporal behaviour of the density matrix the induced polarization can be determined. We intend to expose a diode laser to phase conjugate feedback from an external phase conjugate mirror. Various interesting phenomena have been predicted theoretically. Depending on parameters such as feedback rate and frequency mismatch between pump- and probe frequency the diode laser can be found in different regimes of operation: The frequency of the diode laser can lock to the pump frequency or show self-pulsing behaviour initially with a frequency close to the relaxation frequency but for higher feedback rates these can turn into irregular or even chaotic pulsations.