Terms Of Wave Optics Research Articles

Characterization of Monochromatic Aberrated Metalenses in Terms of Intensity-Based Moments.

Consistent with wave-optics simulations of metasurfaces, aberrations of metalenses should also be described in terms of wave optics and not ray tracing. In this respect, we have shown, through extensive numerical simulations, that intensity-based moments and the associated parameters defined in terms of them (average position, spatial extent, skewness and kurtosis) adequately capture changes in beam shapes induced by aberrations of a metalens with a hyperbolic phase profile. We have studied axial illumination, in which phase-discretization induced aberrations exist, as well as non-axial illumination, when coma could also appear. Our results allow the identification of the parameters most prone to induce changes in the beam shape for metalenses that impart on an incident electromagnetic field a step-like approximation of an ideal phase profile.

Semiclassical TEM image formation in phase space

Current developments in TEM such as high-resolution imaging at low acceleration voltages and large fields of view, the ever larger capabilities of hardware aberration correction and the systematic shaping of electron beams require accurate descriptions of TEM imaging in terms of wave optics. Since full quantum mechanic solutions have not yet been established for, e.g., the theory of aberrations, we are exploring semiclassical image formation in the TEM from the perspective of quantum mechanical phase space, here. Firstly, we use two well-known semiclassical approximations, Miller's semiclassical algebra and the frozen Gaussian method, for describing the wave optical generalization of arbitrary geometric aberrations, including nonisoplanatic and slope aberrations. Secondly, we demonstrate that the Wigner function representation of phase space is well suited to also describe incoherent aberrations as well as the ramifications of partial coherence due to the emission process at the electron source. We identify a close relationship between classical phase space and Wigner function distortions due to aberrations as well as classical brightness and quantum mechanical purity.

Modified Lagrange invariants and their role in determining transverse and axial imaging resolutions of self-interference incoherent holographic systems.

The Lagrange invariant is a well-known law for optical imaging systems formulated in the frame of ray optics. In this study, we reformulate this law in terms of wave optics and relate it to the resolution limits of various imaging systems. Furthermore, this modified Lagrange invariant is generalized for imaging along the z axis, resulting with the axial Lagrange invariant which can be used to analyze the axial resolution of various imaging systems. To demonstrate the effectiveness of the theory, analysis of the lateral and the axial imaging resolutions is provided for Fresnel incoherent correlation holography (FINCH) systems.

Interpretation of attenuated-total-reflection dips observed in surface plasmon resonance

We present an interpretation that differs from an accepted explanation for resonance excitation of surface plasmons (SPs) on a metal using an attenuated total reflection (ATR) method. The metal ATR phenomenon is well expressed in terms of wave optics and accompanies an enhanced evanescent field. The ATR curves and the electric field and absorption distributions in the film layer for the noble metals are simulated numerically using electromagnetic wave analysis. The calculation results provide interpretation that the ATR dips are caused by an absorption loss of the metals produced by enhanced electric fields rather than the energy loss of a transfer excitation to the SPs: the damping loss converted into the SPs or the damping absorption of the once-converted propagation SPs. The sharp ATR dips do not necessarily demonstrate the high-resonance excitations of the SPs, and the metal ATR phenomenon is not restricted to the SPR.

Hidden surface removal in full‐parallax CGHs by silhouette approximation

AbstractIn this paper we report a method of removing hidden surfaces in full‐parallax computer‐generated holograms. First, we examine the handling of light shielding by tilted patches in terms of wave optics, and then propose a silhouette approximation. In addition, we derive a recurrence formula to synthesize object light waves with hidden surface removal by the proposed method. We show that appearance of optically reconstructed surface object of the full‐parallax holograms generated by the proposed method varies in a natural manner as the observation point is changed. This study achieves hidden surface removal in full‐parallax holograms, which was believed to be possible only if vertical parallax is ignored. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(6): 53–61, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20345 Copyright © 2004 Wiley Periodicals, Inc.

Backscattering in single-mode fibres

The scattering process in single-mode optical fibres is considered in terms of wave optics rather than geometrical optics, which is inadequate in this case. Surprisingly, however, the result for the backscattering signal at the input end of the fibre is nearly the same as for multimode fibres.

Transverse shift by total reflection of a circularly polarised light beam: theory and experimental proof

The Goos and Hanchen experiments of 1947 have shown that in total reflection the photons tunnel through the second medium (which we take to be the vacuum), whence a longitudinal shift Δx; Imbert's experiments of 1970 have shown that if the incident beam is circularly polarized there is also a transverse shift Δz, the sign of which depends on the helicity sign. We briefly explain this new phenomenon, first in terms of a generalized geometrical optics where the velocity and momentum of a spinning photon are non-collinear, then in terms of wave optics, using an appropriate class of solutions of Maxwell's equations.

The theory of the Christiansen experiment

The effects exhibited by a Christiansen filter can only be explained or understood in terms of wave-optics. A theoretical formula is derived in the paper for the distribution of intensity in the spectrum of the transmitted light, the variables involved being the wave-length of the light, the average size of the particles of the powder, the thickness of the cell and the difference in the refractive indices of the powder and the liquid for the wave-length under consideration. The characters of the halo observed around the light source are also discussed in terms of diffraction theory. The theory explains the facts of observation in a very simple manner and gives results in satisfactory accord with the available experimental data.