ИСТИНА

We describe the dark states of singlet form in which the atomic ensemble cannot emit or absorb a photon. Such states can be fabricated via Stark shift of energy induced by the external potential that we can switch on and off. The portion of dark states obtained by this way reaches few percent and can be made up to 50% by the proper choice of potential changes in the time. Dark states can be used for the building of the secure quantum lock, which guarantees the high level of security when compared with classical method of secure access.