In this study, we explored the possibility of enhanced spontaneous emission of radiation beyond the free space value by analyzing a semiconductor superlattice structure placed in a microcavity whose resonant modes were tuned to the Bloch frequency. In particular, we considered the spontaneous emission of Bloch radiation into the dominant mode of a rectangular waveguide. In the analysis, the quantum radiation field was described by the waveguide quantized electromagnetic field in the Coulomb gauge, and the instantaneous eigenstates of the Bloch Hamiltonian were used as basis states to analyze the Bloch dynamics to all orders in the constant external electric field.The results predict that the spontaneous emission occurs with frequencies equal to integral multiples of the Bloch frequency without any ad hoc assumptions made concerning the existence of Wannier-Stark ladder levels; such quantization effects arise from a natural consequence of the implicit quantum selection rules. It was shown that the power radiated into the dominant mode of a rectangular waveguide can be enhanced by an order of magnitude in comparison with that for the free space spontaneous emission by tuning the Bloch frequency to align with the spectral region of the waveguide spectral density peak. For GaAs-based superlattices, the power radiated from spontaneous emission due to Bloch oscillations in the terahertz frequency range was estimated to be about several microwatts.
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49577.1-EL-IIIn this study, we explored the possibility of enhanced spontaneous emission of radiation beyond the free space value by analyzing a superlattice structure placed in a microcavity whose resonant modes were tuned to the Bloch frequency. In particular, we considered the spontaneous emission of Bloch radiation into the rectangular waveguide dominant mode.In the analysis, the quantum radiation field was described by the waveguide quantized electromagnetic field in the Coulomb gauge, and the instantaneous eigenstates of the Bloch Hamiltonian were used as basis states to analyze the Bloch dynamics to all orders in the constant external electric field. The results predict that the spontaneous emission occurs with frequencies equal to integral multiples of the Bloch frequency without any ad hoc assumptions made concerning the existence of Wannier-Stark ladder levels; such quantization effects arise from a natural consequence of the implicit quantum selection rules.It was shown that the power radiated into the dominant mode of a rectangular waveguide can be enhanced by an order of magnitude in comparison with that for the free space spontaneous emission by tuning the Bloch frequency to align with the spectral region of the waveguide spectral density peak. For GaAs-based superlattices, the power radiated from spontaneous emission due to Bloch oscillations in the terahertz frequency range was estimated to be about several microwatts.
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