Single-photon blockade in doubly resonant nanocavities with second-order nonlinearity

Abstract

We propose the use of nanostructured photonic nanocavities made of χ (2) nonlinear materials as prospective passive devices to generate strongly sub-Poissonian light via single-photon blockade of an input coherent field. The simplest scheme is based on the requirement that the nanocavity be doubly resonant, i.e. possess cavity modes with good spatial overlap at both the fundamental and secondharmonic frequencies. We discuss feasibility of this scheme with state-of-the art nanofabrication technology, and the possibility to use it as a passive single-photon source on-demand.

Unconventional photon blockade in doubly resonant microcavities with second-order nonlinearity

“…As a consequence, strong photon antibunching is obtained also for g nl κ, relaxing the requirements of Ref. 10. Simultaneously, given that the nonlinear shift in the effective Kerr model is given by g 2 nl /∆ 3 , the UPB also allows to relax the doubly resonant condition, i.e.…”

“…It has been recently proposed that single-photon blockade could be achieved in nanostructured cavities either with second-[χ (2) ] [10] or third-order [χ (3) ] [11] nonlinear susceptibility, which can be strongly enhanced by diffraction-limited photonic confinement [12,13]. On the other hand, given the small values of typical nonlinear coefficients of most semiconducting and insulating materials [14], an unconventional photon blockade (UPB) process could facilitate achieving antibunched light emission from suitably engineered coupled modes [15].…”

“…The latter is coupled to theâ 2 mode by the second-order nonlinear coefficient, g nl , enhanced by the doubly resonant condition [10], while the nonlinear optical properties of modeâ 1 are assumed to be negligible. We notice that previous studies on UPB with Kerr-type nonlinearity have shown that assuming a nonlinear response also in the driven cavity does not significantly affect the result [17].…”

“…In particular, with the simplifying assumption that fundamental and second-harmonic modes have a large spatial overlap [10], such term is approximately reduced to g nl ε 0 [ω 2 /(ε 0 ε r )] 3/2χ (2) / √ V eff , whereχ (2) gives a scalar approximation for the second-order susceptibility tensor, χ (2) ijk , coupling the relevant fundamental and second-harmonic field components, respectively [27]. In the latter expression, V eff is an effective volume arising from the confinement of the classical field profiles in the resonator, assumed to be described by a normalized scalar function f (r) such that |f (r)| 2 d 3 r = 1.…”

“…10 to obtain conventional single-photon blockade in photonic microcavities made of a high-χ (2) nonlinear material -such as, e.g., III-V semiconductors (GaAs, GaP, GaN, AlN, etc.) -and fulfilling a doubly resonant condition -i.e.…”