Comparison between ultrathin phonon polariton modes in monolayer hexagonal boron nitrides

The dispersion properties and characteristics of monolayer hexagonal boron nitrides (hBN) supported by transverse magnetic (TM) and transverse electric (TE) phonon polaritons in the air-hBN-air structure have been extensively studied. The analytical results show that the hBN based TM (TE) phonon polaritons exist in Restsrahlen bands when imaginary surface conductivity is positive (negative). The effective mode indexes of TM phonon polaritons are much higher than those of TE phonon polaritons, with respective values of and which makes TM more promising in practical realization. In addition, the propagation length of TE polaritons is less lossy and surpasses that of TM polaritons by factor . This paper compares these important properties and sheds more insight into their applications in photonics and optoelectronic devices.