Optical Feshbach Resonance Using the Intercombination Transition

We report control of the scattering wave function by an optical Feshbach resonance effect using ytterbium atoms. The narrow intercombination line (${}^{1}S_0-{}^{3}P_1$) is used for efficient control as proposed by Ciuryło et al. [Phys. Rev. A 71, 030701(R) (2005)]. The manipulation of the scattering wave function is monitored with the change of a photoassociation rate caused by another laser. The optical Feshbach resonance is especially efficient for isotopes with large negative scattering lengths such as ${}^{172}\mathrm{Yb}$, and we have confirmed that the scattering phase shift divided by the wave number, which gives the scattering length in the zero energy limit, is changed by about 30 nm.

Figure 1

Sketch of energy levels, potentials, scattering wave functions, and lasers relevant to this experiment. The frequency of the laser $L_1$ is tuned near a PA resonance to modify the scattering wave function $F(r;\eta )$ in the ground ${}^1\Sigma _g{}^{+}$ state. In this figure the phase shift $\eta$ is assumed to be a real value. The frequency of the other laser $L_2$ is fixed at another PA resonance to monitor the value of $|F(r_{t,2};\eta ){|}^2$ through the change of its PA rate.

Figure 2

(a) Atom-loss spectra for ${}^{172}\mathrm{Yb}$ with applying only $L_1$ (solid circles) and with applying both $L_1$ and $L_2$ (open circles). The numbers of atoms without applying the lasers and with applying only $L_2$ are shown as the solid square and the open square, respectively. Their standard deviations are also shown as the error bars. The theoretical spectral profiles are also shown as the lines. The frequency for ${\Delta }_1=0$ is located at $-795.7\mathrm{MHz}$. (b) Real part $\delta$ of the phase shift $\eta$ and the inelastic collision rate coefficient $K_{\mathrm{PA},1}$ corresponding to the theoretical spectra.

Figure 3

(a) Atom-loss spectra for ${}^{176}\mathrm{Yb}$ with applying only $L_1$ (solid circles) and with applying both $L_1$ and $L_2$ (open circles). The numbers of atoms without applying the lasers and with applying only $L_2$ are shown as the solid square and the open square, respectively. Their standard deviations are also shown as the error bars. The theoretical spectral profiles are also shown as the lines. The frequency for ${\Delta }_1=0$ is located at $-872.1\mathrm{MHz}$. (b) Real part $\delta$ of the phase shift $\eta$ and the inelastic collision rate coefficient $K_{\mathrm{PA},1}$ corresponding to the theoretical spectra.