Matter Coupling to Strong Electromagnetic Fields in Two-Level Quantum Systems with Broken Inversion Symmetry

Abstract

We demonstrate theoretically the parametric oscillator behavior of a two-level quantum system with broken inversion symmetry exposed to a strong electromagnetic field. A multitude of resonance frequencies and additional harmonics in the scattered light spectrum as well as an altered Rabi frequency are predicted to be inherent to such systems. In particular, dipole radiation at the Rabi frequency appears to be possible. Since the Rabi frequency is controlled by the strength of the coupling electromagnetic field, the effect can serve for the frequency-tuned parametric amplification and generation of electromagnetic waves. Manifestation of the effect is discussed for III-nitride quantum dots with strong built-in electric field breaking the inversion symmetry. Terahertz emission from arrays of such quantum dots is shown to be experimentally observable.

The New Concept of Nano-Device Spectroscopy Based on Rabi–Bloch Oscillations for THz-Frequency Range

“…Its physical origin is similar to the so-called low-frequency RO in the two-level quantum systems with broken inversion symmetry [10]. As was predicted in [10], it leads to non-zero diagonal matrix elements of dipole moment. It is impossible for real atoms (excluding hydrogen), but implementable for artificial atoms (for example, self-organized semiconductor quantum dots).…”

Asymmetric quantum dot in a microcavity as a nonlinear optical element

“…This means that all transitions |ψ ± n → |ψ ± m are allowed and emission spectrum contains frequencies (n− m) ω c ± Ω ′ R . However, the intensity of the transitions decreases with increasing (n − m) because of decreasing the Bessel functions J k (x) with increasing k [20]. Therefore, most intensive ones correspond to those depicted at Fig.…”

“…On the other hand, the incorporation of the asymmetry into the quantum system can radically change its emission pattern and lead to the opening of optical transitions which were forbidden in the symmetric case. Particularly, the breaking of inversion symmetry opens optical transitions at the Rabi frequency at QDs placed in strong external laser field [20]. The similar effect occurs for asymmetric quantum wells placed inside a planar microcavity [21,22].…”

Carrier-envelope phase-dependent transmitted spectra in inversion-asymmetric media with permanent dipole moments

“…More importantly, it should be pointed out that our result is not limited to the certain asymmetric molecule, but can be extended to other inversion-asymmetric media which have a nonzero PDM. For example, a Rydberg hydrogen atom imposed to a homogeneous static field, confined semiconductor nanostructures, quantum dots, etc, can serve as prospective systems for observation of the effect (see the discussion in [45]). …”