Fundamental interactions, spectroscopy & lasers |
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Dr Patrick E G Baird
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SymmetryThe use of lasers in atomic physics offers very sensitive techniques to test for violations of the discrete symmetries: parity (P), charge conjugation (C) and time reversal (T). In particular, experiments sensitive to P-, PT-, T- and CPT- violations provide tests of fundamental physical theories. Violation of P-symmetry is connected with tests of electroweak theory while tests of any PT- or T- violation can be related to CP- violation detected in neutral kaon decay. The experimental techniques involve optical polarimetry, spectroscopy, optical pumping, trapped atoms and interferometry. Atomic Hydrogen Simple one-electron systems form the cornerstone of fundamental atomic theory including bound-state quantum electrodynamics (QED). Furthermore, the comparative simplicity of the energy level structure leads to a natural progression of transition frequencies spanning the microwave to the vacuum ultraviolet. A collaborative project with the NPL seeks to exploit the development of femtosecond combs to make precise measurements on excited states. Solid State Lasers Work on very narrow optical transitions requires suitable lasers. To this end, work is being pursued on narrowing the bandwidth of a Ti:sapphire system as well as developing a didode pumped, mode-locked, solid state system based on Cr:LiSAF. Finally, laser systems which can be exploited to cool atomic hydrogen are being investigated, including a narrow bandwidth, pulsed alexandrite system.
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Key PublicationsAn Interferometric Test of Time Reserval Invariance in Tatoms Measurement of the 1s-2s energy interval in muomium Meyer V., Bagayev S.N., Baird P.E.G. et
al A chirp-compensated, injection seeded alexandrite laser. A measurement of the caesium 6s-8p transition frequency. Two-photon spectroscopy in poassium Optical pumping in thallium: spectroscopy, coherent and
linewidths Review Parity violation and time reversal invariance
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