Motivated by the recent experiment by Oosterkamp et al. [Nature 395, 873 (1998)] we have developed a theory to describe electron tunneling through two coupled quantum dots irradiated by a microwave field. Our results for both the weak- and strong-coupling regimes are in excellent agreement with experiment. In addition, our theory suggests several unique features in the strong-coupling regime, including Rabi oscillations, which can be verified experimentally. The main resonance and the sideband resonance of the molecular level are also calculated for the entire range of the coupling strength, and show interesting crossover behavior.published_or_final_versio
