Transfer of arbitrary quantum emitter states to near-field photon superpositions in nanocavities

Abstract

We present a method to analyze the suitability of particular photonic cavity designs for information exchange between arbitrary superposition states of a quantum emitter and the near-field photonic cavity mode.As an illustrative example, we consider whether quantum dot emitters embedded in "L3" and "H1" photonic crystal cavities are able to transfer a spin superposition state to a confined photonic superposition state for use in quantum information transfer. Using an established dyadic Green's function (DGF) analysis, we describe methods to calculate coupling to arbitrary quantum emitter positions and orientations using the modified local density of states (LDOS) calculated using numerical finite-difference time-domain (FDTD) simulations. We find that while superposition states are not supported in L3 cavities, the double degeneracy of the H1 cavities supports superposition states of the two orthogonal modes that may be described as states on a Poincaré-like sphere. Methods are developed to comprehensively analyze the confined superposition state generated from an arbitrary emitter position and emitter dipole orientation.

Nanoscale nonreciprocity via photon-spin-polarized stimulated Raman scattering

“…We also note that while the necessary pump irradiances are high, they are achievable; and considering the generality of spin-dependent SRS and the fact that Q factors of >10 4 have been measured in structures like those considered here, much lower pump thresholds should be possible 51,53 . Additionally, similar dipolar mode profiles can be generated in high Q L1 and H1 photonic crystal defect cavities 63,64 . Due to the reduced mode volume of these structures, the required power densities for SRS could be met with just a few milliwatts, comparable to active integrated magneto-optical isolators 65 .…”

Engineering strong chiral light-matter interactions in a waveguide-coupled nanocavity

“…To increase the intrinsic quality factor (Q fac- tor) of the cavity, the innermost holes (marked blue) are displaced outwards by 0.09a and have their radius reduced by 0.09a. The resulting cavity supports two orthogonal modes labelled χ and ψ (as in Thijssen et al 28 ), each with a Q factor of ∼34000 and centred at ∼924.5 nm. The mode spectrum and spatial field profiles of the H1 cavity are shown in Figure 1b-d.…”

“…The results discussed above were obtained from independent excitation of each mode, whilst we wish to excite the modes simultaneously using a single QE with a circularly polarised transition. The circular dipole will excite a superposition of the two cavity modes 28 with a known phase difference (±π/2, depending on the dipole handedness). This alone will not lead to directional emission, as the phase difference between the fields in one waveguide will be +π/2, and in the other will be −π/2.…”

Polarization tuning of an H1 organic–inorganic nano-cavity

“…3 for = 0.14 . Here it is apparent that both modes M x and M y have a dipolelike field distribution 26,38 . We can use this calculated field distribution to explain the finding (see Fig.…”