Magnetopolaron effects in light reflection and absorption of a three-level system in a QW

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The light absorption A and reflection coefficients for a three-level system in a quantum well (QW) in a strong magnetic field H, directed perpendicularly to the QW's plane, have been calculated. The energy levels correspond to the ground state and to magnetopolaron energy levels ℏω₁₍₂₎ with the inverse lifetimes γᵣ₁₍₂₎ and γ₁₍₂₎. The inverse radiative lifetime of an EHP in a QW γᵣξ(K⊥)=0 only under condition K⊥≤ωξn/c, where ℏωξis the EHP energy. It has been shown that γᵣξ(K⊥) is proportional to H. The values γra(K⊥) and γrb(K⊥) for an excitation consisting of a hole and a usual magnetopolaron have been calculated. The index a(b) designates a magnetopolaron upper (lower) term. In the resonance at Hres=mₑcωLO/|e| γrares=γrbres=γᵣξ₀res/2, where the index ξ₀ corresponds to the EHP with nₑ=nₕ=1. The dependencies A(H) and R(H) for various values of ωₗ in the magnetophonon resonance vicinity have been obtained. The existence of "combined"and "weak" polarons has been predicted. The resonant value Hres for the combined polaron case depends on a QW's depth and width.