Role of Standing-Wave Mode Structure in Microlaser Emission
We have developed the first working microlaser, a laser oscillator in which coherent light is generated by means of the interaction of a single, excited two-level atom with a single mode of the radiation field. i In this experiment, inverted two-level atoms in an atomic beam traversing an ultrahigh Q optical resonator interact with the cavity mode one by one, and emit photons into the resonator. Because of the long cavity storage time, a large number of photons can build up. In this device the photon generation process follows the Jaynes-Cummings model, and the emission process is significantly different from that of conventional lasers. Photon build up is initiated by vacuum Rabi oscillations, not by spontaneous emission as in conventional lasers. Furthermore, amplification of the field is accomplished by the quantized Rabi oscillation process, and under appropriate conditions highly nonclassical photon distributions can be generated, such as photon-number trapped states.’ The microlaser is the optical analog of the micromaser,3 which operates in the microwave regime. However, operation in the optical range provides new experimental opportunities associated with the large increases in photon energy and momentum. The increase in photon energy allows measurement of the microlaser mean photon number and emission spectrum 4 via direct photon detection, whereas only atoms can be probed in the micromaser. The increased photon momentum should make it possible to study the entanglement of the quantized Rabi oscillations with the mechanical degrees of freedom of the atom, as exchange of a single optical photon with the cavity field can significantly deflect the atomic trajectory.5 In addition, the absence of blackbody radiation at optical frequencies opens the possibility of studying the features of quantum collapse and revival,6 which are entirely due to the superposition of discrete photon-number Fock states in the cavity field. Also promising is the possibility of generating and studying photon-number trapped states.
KeywordsCavity Mode Photon Number Blackbody Radiation Cavity Field Rabi Oscillation
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