Figure 2

Comparison of absorption spectra driven by bichromatic control field (blue) and single control field (red). (a) \(\Omega _{m} = 0\) and (b) \(\Omega _{m} = 0.5\Gamma \). Other parameters are \(\Omega _{c1} = \Omega _{c2} = 1\Gamma \), \(\Delta _{c1} =\Delta _{m} = 0\), \(\delta = 6\Gamma \), \(\gamma _{21} =\Gamma = 2\pi \times 6\) MHz, \(\gamma _{31} = 2\pi \times 1\) kHz and \(\gamma _{41} = 2\pi \times 0.5\) kHz