Controllable coherent perfect absorption in a composite film

Abstract

We exploit the versatility provided by metal-dielectric composites to demonstrate controllable coherent perfect absorption (CPA) or anti-lasing in a slab of heterogeneous medium. The slab is illuminated by coherent light from both sides, at the same angle of incidence and the conditions required for CPA are investigated as a function of the different system parameters. Our calculations clearly elucidate the role of absorption as a necessary prerequisite for CPA. We further demonstrate the controllability of the CPA frequency to the extent of having the same at two distinct frequencies even in presence of dispersion, rendering the realization of anti-lasers more flexible.

Perfect absorption and no reflection in disordered photonic crystals

“…Among them, unidirectional reflectionless (URL) media [1][2][3], where reflection from one side is significantly suppressed, and coherent perfect absorption (CPA) media [4][5][6][7][8][9][10], where the two-sided incident waves are completely quenched, are extensively studied wave phenomena, especially in optics [6,[9][10][11][12][13][14][15][16][17]. On-chip implementation of URL media, e.g., is expected to underpin a new generation of photonic devices [18], while CPA media clearly provides an additional flexibility to tune absorption when compared to perfect one-port absorbers.…”

Synthesis of tunable plasmonic metal-ceramic nanocomposite thin films by temporally modulated sputtered fluxes

“…The LSPR gives rise to a strong absorption around the resonance energy 1 and can lead to an intense coloration of the material 2 . It also results in a strong localized enhancement of the electric field around the nanoparticles making these materials interesting for a number of applications, such as sensors 3 , absorbers [4][5][6] , substrates for surface enhanced Raman scattering 7 , optically active materials 8,9 and materials exhibiting an enhanced magnetooptical coupling 10 . The energy position and width of the absorption, as well as the plasmonic properties in such a nanocomposite, depend on the dispersion of the electromagnetic radiation in the dielectric matrix in combination with the bulk optical properties of the metal nanoparticle, the nanoparticle size and shape, and the inter-particle separation 11,12 .…”

Light-controlled perfect absorption of light

“…The former is achieved in a critically coupled system [1][2][3][4], while the the latter is referred to as coherent perfect absorption (CPA) [5][6][7][8]. Both the phenomena are based on 'perfect' destructive interference, demanding equality of the amplitudes of the interfering waves, having a phase difference of odd multiples of π.…”

“…In this paper we address a more fundamental issue of coherent perfect absorption in a Kerr nonlinear slab. In order to make connection with earlier work on a linear system [6], we consider the slab of a metal-dielectric composite medium assuming it to have an overall Kerr nonlinearity. Recall that a rigorous theory for heterogeneous medium with nonlinear inclusions or host exists [14,15], which leads to a complex susceptibility χ (3) having nonlinear absorption as well.…”