As for dielectric, we will use several materials. The value of its dielectric constant is taken from the experimental work 39. We will use silver as an example of metal. In the following, we demonstrate how the proposed structure can be used to control the properties of the metamaterial, the dispersion of a surface plasmon, and the value of the Purcell factor. 1a), two surface plasmon states will appear, which we will accordingly call ordinary and extraordinary plasmons. If this metamaterial is stacked with a cladding with dielectric constant ε 1 (see Fig. In such medium, two possible types of waves can propagate: ordinary and extraordinary. This paper is aimed at the investigation of the parameters of the metamaterials and dielectric on the spectrum of the Purcell coefficient using effective media approach and numerical modelling. Also, it is interesting to investigate limits of applicability of effective media approach to the analysis of the Purcell effect in metamaterial-based structures. Further, the dependence of the value of the Purcell factor on the metal filling factor seems to be out of scope of aforementioned papers creating a gap between dispersion studies 25– 31 and Purcell effect studies, which we aim to cover. These works deal with various aspects of the Purcell effect in metamaterials but are similar since they are always considered the dipole placed at some distance from the interface, which is either arbitrary or dictated by experimental or numerical conditions. It was also shown theoretically and experimentally that in layered metamaterials photonic LDOS can be enhanced 32– 38 leading to a pronounced Purcell effect. Shifting of dispersion dependence towards lower energy is demonstrated for various 2D and 3D plasmonic metamaterials (MM) 25– 28, and for layered metamaterials 29– 31. In such materials bulk metal is replaced with structured one and EPF defines the properties of the structures instead of plasma frequency of metal. Nevertheless, the existence of features in the dispersion curve suggests that the effective utilization of the surface plasmons still can be achieved 22.Ī possible way to obtain higher magnitudes of the enhancement of the spontaneous emission probability is to shift the LDOS peak to the low frequency range, where absorption is lower via application of “effective plasma frequency” (EPF) concept 23, 24. However, this conclusion has been argued 20 in recently published paper 21, where it was demonstrated that for the frequency range, where the LDOS peak is occurring, this enhancement is dramatically reduced due to light absorption in metals. Previously, it was proposed that the major enhancement of the spontaneous emission probability can be achieved in plasmonic structures due to a high local density of states (LDOS) 19. The latter phenomenon is crucial for increasing the efficiency of light emission in optoelectronic and photonic devices 17, 18. Moreover, a number of spectacular effects caused by surface plasmons can be mentioned 10– 13, in particular, a surface-enhanced Raman scattering 14, 15 and the Purcell effect 16, which is the enhancement of spontaneous emission probability in an inhomogeneous medium. For example, field localization provides possibilities for the development of subwavelength optical devices 6, 7, while the increased amplitude of the field near the interface allows to utilize such systems in sensor devices 8, 9. Due to the formation of such states, metal-dielectric structures can facilitate a strong light-matter interaction and therefore attract significant research interest 2– 5. Surface plasmon, a localized state of an electromagnetic field at the interface between a metal and a dielectric, was predicted more than sixty years ago 1.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |