E. Popov

Zero order anomaly of dielectric coated gratings

Abstract The zeroeth order diffraction efficiency of a three-layer dielectric grating is studied theoretically and experimentally. A sharp resonance anomaly due to the excitation of guided waves is observed, which increases significantly the reflectance of the system. The operation of the structure as a tunable narrow-band wavelength filter in a reflection regime is demonstrated.

Diffraction efficiency anomalies of multicoated dielectric gratings

Abstract The diffraction efficiency curves of multicoated dielectric gratings are measured as a function of wavelength and angle of incidence for S and P polarization in the visible region. Strong anomalies are observed, due to the excitation of guided waves in the grating.

Gratings—general Properties of the Littrow Mounting and Energy Flow Distribution

Abstract Quasi-periodicity under certain conditions of the dependence of grating properties on groove depth is explained from the point of view of energy flow distribution (EFD). The formation of curls in flow maps is followed as a function of the groove depth h for two general types of gratings having one or two propagating diffraction orders. An equivalence between shallow and deep gratings is established: the EFD above the grooves is one and the same, while in deep gratings a definite number of curls exists, totally hidden inside each groove. Perfect blazing and antiblazing are connected with the position of these curls with respect to the top of the grooves.

Losses of Plasmon Surface Waves on Metallic Grating

Abstract Diffraction and absorption losses of plasmon surface waves (PSW) propagating along a metallic grating are investigated numerically as a function of groove depth. A periodicity of diffraction losses is found to exist. The energy flow distribution (EFD) above and inside the grooves is calculated and a similarity between the PSW on shallow and deep gratings is established above the grooves, while inside the grooves of deep gratings totally hidden curls in EFD are found to form.

Total absorption of light by a sinusoidal grating near grazing incidence.

A heretofore unknown total absorption phenomenon on a diffraction grating has been demonstrated both theoretically and experimentally. It occurs only in a series of six special conditions, namely, groove shape, angle of incidence, groove frequency, depth modulation, polarization, and metal surface. None of the classical explanations for grating anomalous behavior seems to correspond to this case.

Electromagnetic field enhancement in deep metallic gratings

Abstract Abnormally high light absorption in metallic gratings due to resonance anomaly is shown to lead to electromagnetic field enhancement in the very near vicinity of grating surface. 3D field distributions are compared depending on the groovedepth. It is shown numerically that for deep gratings the electromagnetic field is localized on the top of the groove, contrary to shallow gratings where the resonance anomalies lead to field enhancement both on the top and in the bottom of the groove.

Scalar theory of transmission relief gratings

Abstract A simple formula is derived that allows evaluation by a single integration the diffraction efficiencies of transmission relief gratings when they support a great number of orders. Validity of the method is demonstrated by comparison with a rigorous differential method.

Diffraction from planar corrugated waveguides at normal incidence

Abstract The effect of normal incidence mode excitation in a corrugated waveguide is studied theoretically. The behaviour of the reflectance is explained by a phenomenological approach.

Dispersion characteristics of multilayer waveguides

Abstract The dispersion characteristics of planar multilayer optical waveguides have been calculated. It was found that splitting and degeneration of the modes occur, if the thickness of the intermediate layer between two waveguides is small.

Back-side diffraction by relief gratings

Abstract A comparison is made between the efficiency of bare and aluminum coated dielectric diffraction gratings supporting only two propagating orders utilizing substrate side light incidence. A large dissimilarity between the two types of gratings is observed and a possibility to achieve a 100% value of the absolute diffraction efficiency in Littrow mount is discussed. An almost constant value of 80% of efficiency is preserved for the aluminum grating nearly in the entire visible region.