Tunable routing properties of single photon interacting with two quantum dots in a quantum router with the工-type coupled cavity waveguide system

A theoretical model of 工-shaped coupled-cavity waveguide with two quantum dots is proposed to realize the single photon router, where the two quantum dots are embedded in two nodes of two infinite coupled-cavity and a finite coupled-cavity waveguide respectively. Based on the discrete scattering equations, the routing properties such as transmission, reflection, and the transfer rate of the incident single photons are theoretically investigated. It is found that they can be controlled by various parameters such as the coupling strength between two quantum dots and three coupled-cavity waveguides, the transition energies of two quantum dots, wave vector, and the energy of the incident single photons, etc. Especially, when $$\omega_{e}^{(1)} = \omega_{e}^{(2)} = 10$$ ω e ( 1 ) = ω e ( 2 ) = 10 , in case of $$k = 2n{\pi \mathord{\left/ {\vphantom {\pi 4}} \right. \kern-0pt} 4}\,(n = 1,2,...)$$ k = 2 n π π 4 4 ( n = 1 , 2 , . . . ) ,the incident single photons have two symmetric peaks with relative to the resonant energy, but in case of $$k = (2n + 1){\pi \mathord{\left/ {\vphantom {\pi 4}} \right. \kern-0pt} 4}\,(n = 0,1,2,...)$$ k = ( 2 n + 1 ) π π 4 4 ( n = 0 , 1 , 2 , . . . ) , there appears only one transfer peak with blue or red shift due to the quantum interference between the two quantum dots. The tunable routing properties of the single photons in the 工-shape quantum router might have potential applications for future quantum devices. Graphical abstract