Measurement of the tune-out wavelength for 133Cs at 880 nm

Abstract

We perform a measurement of the tune-out wavelength, λ0, between the D1, 62S1/2→62P1/2, and D2, 62S1/2→62P3/2, transitions for 133Cs in the ground hyperfine state (F=3,mF=+3). At λ0, the frequency-dependent scalar polarizability is zero leading to a zero scalar ac Stark shift. We measure the polarizability as a function of wavelength using Kapitza-Dirac scattering of a 133Cs Bose-Einstein condensate in a one-dimensional optical lattice, and determine the tune-out wavelength to be λ0=880.21790(40)stat(8)sys nm. From this measurement we determine the ratio of reduced matrix elements to be ∣∣⟨6P3/2∥d∥6S1/2⟩∣∣2/∣∣⟨6P1/2∥d∥6S1/2⟩∣∣2=1.9808(2). This represents an improvement of a factor of 10 over previous results derived from excited-state lifetime measurements. We use the present measurement as a benchmark test of high-precision theory.