Photons made by vacuum-stimulated Raman scattering in an optical cavity

Summary form only given. Many attempts to realize elementary quantum-logic gates as well as the feasible schemes for quantum cryptography and quantum teleportation are based on the availability of a single photon in a well defined mode of the radiation field. However, most employed schemes used for photon generation rely on spontaneous processes or on parametric down conversion and produce photons at more or less random times. Only recently, different photon generation schemes have been demonstrated, like a single-photon turnstile device, based on the Coulomb blockade mechanism in a quantum dot, the fluorescence excitation of a single molecule or the excitation of single colour centers or quantum dots. All these new schemes emit photons upon an external trigger event. However, the photons are spontaneously emitted into many modes of the radiation field and usually show a broad energy distribution. In contrast to these, our scheme leads to a photon emission into a single mode of the electromagnetic field of a high-Q optical cavity.