AOS News - The Australian Optical Society - Macquarie University

• Theory• Expt.33.0He Lamb shift history34.0 35.0 36.02P - 1S : Herzberg, 1958•Schwartz, 1961Aashamar and Austvik, 19771S - 2Ptogether with my colleagues at MacquarieUniversity we have created a new lightsource that overcomes the inherentfrequency-chirp limitations of the originaldye laser sources used in the NISTand Amsterdam experiments. We havedeveloped an all solid state OpticalParametric Oscillator (OPO) -basedsystem with well-characterised, near-zerofrequency chirp characteristics [16]. Withthis system, we hope to undertake a futuremeasurement that will – along with themore recent Amsterdam experiments –challenge QED theory to better than 10MHz.In this way, better measurementtechniques will enable more stringent testsof fundamental science, which will in turn•Sucher, 1958••Drake et al.; Morgan, et al., 1993Eikema et al., 1993Eikema et al., 1996{ Eikema et al., 1997Drake, 19971S - 2S NIST, 199837.038.0GHzEikema et al., 2010Yerokhin and Pachucki , 201039.040.041.0• Drake, 1988•••••50 MHz(laserν chirp)Figure 5. Theoretical and experimental determinations of the helium ground stateLamb shift with uncertainty levels shown.••42.043.0allow better understanding to underpindevelopment of new technologies, that willenable even more precise measurements.The encouragement that the Barry InglisMedal provides to such investigationsreflects the central role played by theNational Measurement Institute in drivingprecision measurement in Australia, and itis with great pleasure that I humbly acceptthis award.AcknowledgementsI would like to acknowledge thecontributions made to this work by mymany colleagues, in particular at theANU, NIST and Macquarie University.ReferencesAOS News Volume 25 Number 1 2011[1] Bureau International de Poids etMesures (BIPM – the InternationalBureau of Weights and Measures)http://www.bipm.org/en/si/si_brochure/chapter2/2-1/second.html[2] K.G.H. Baldwin, Contemp. Phys. 46(2), 105-120 (2005).[3] L.J. Uhlmann, R. Dall, A.G. Truscott,M.D. Hoogerland, K.G.H. Baldwinand S.J. Buckman. Phys. Rev. Lett.94 (17), 173201 (2005).[4] T. Zelevinsky, D. Farkas, and G.Gabrielse, Phys. Rev. Lett. 95, 203001(2005).[5] G. Giusfredi et al., Can. J. Phys. 83,301-310 (2005).[6] J.S. Borbely et al, Phys. Rev. A 79,060503(R) (2009).[7] G.W.F. Drake, Can. J. Phys. 80,1195-1212 (2002).[8] K. Pachucki, Phys. Rev. Lett. 97,013002 (2006).[9] K. Pachucki and V.A. Yerokhin, Phys.Rev. A 79, 062516 (2009).[10] H. W. Moos and J. R.Woodworth, Phys. Rev. A 12, 2455(1975).[11] R. G. Dall, K. G. H. Baldwin,L. J. Byron and A. G. Truscott, Phys.Rev. Lett. 100, 023001 (2008).[12] S.S. Hodgman, R.G. Dall,L.J. Byron, K. G. H. Baldwin, S.J.Buckman and A.G. Truscott, Phys.Rev. Lett. 103, 053002 (2009).[13] S.S. Hodgman, R.G. Dall, K. G.H. Baldwin, and A.G. Truscott, Phys.Rev. A 80, 044501 (2009).[14] S.D. Bergeson, A. Balakrishnan,K.G.H. Baldwin, T.B. Lucatorto,J.P. Marangos, T.J. McIlrath, T.R.O’Brian, S.L. Rolston, C.J. Sansonetti,Jesse Wen, N. Westbrook, C. H.Cheng and E. E. Eyler, Phys. Rev.Lett. 80 (16), 3475 - 3478 (1998).[15] K. S. E. Eikema, W. Ubachs, W.Vassen, and W. Hogervorst, Phys.Rev. A 55, 1866–1884 (1996).[16] Y. He, M. Kono, R.T. White,M.J. Sellars, K.G.H. Baldwin and B.J.Orr, Appl. Phys. B 99(4), 609 - 612(2010) and references therein.Figure 6. Professor Ken Baldwin (Centre) discussing with Barry Inglis (left) and theHonorable Richard Marles (right), Parliamentary Secretary responsible for the NMI,on the occasion of the award of the Barry Inglis Medal.Professor Ken Baldwin is with theResearch School of Physics andEngineering, Australian NationalUniversity.11