A non-iterative and non-interferometric computational imaging method to reconstruct a complex wave field called synthetic aperture based on Kramers–Kronig relations (KKSAI) is reported. By collecting images through modified microscope system with pupil modulation capability, we show that the phase amplitude profile of sample at limited resolution can be extracted from as few two intensity by us...

A high speed optical wireless-fiber solution was proposed in part I of this research with applications such as network backhaul and data center links. The system is based on the utilization state-of-the-art modulation multiplexing techniques fiber wireless communications, including multicore fibers (MCFs) coherent detection Kramer-Kronig (KK) receivers. In letter, we analyze performance compare...

The "photonic lantern," an optical fibre device that has emerged from the field of astrophotonics, allows for a single-mode photonic function to take place within a multimode fibre. We study and evaluate the modal behaviour of photonic lanterns as well as the conditions for achieving low-loss between a multimode fibre and a "near-diffraction limited" single-mode system. We also present an intui...

The application of generalized Kramers-Kronig relations, the so-called Leontovich relations, to thermal field theory is discussed. Medium effects contained in the full, thermal propagators can easily be taken into account by this method. As examples the collisional energy loss of a charged particle in a relativistic plasma and the radiation of energetic photons from a quark-gluon plasma are con...

We calculate the nondegenerate bound electronic nonlinear refractive index n2 ( w1; w2) (i.e., an index change at frequency w1 due to the presence of a beam at frequency w2) in semiconductors. We calculate this nonlinearity and its disper~ sion using a Kramers-Kronig transformation on the calculated nondegenerate nonlinear absorption spectrum due to two-photon absorption, electronic Raman and o...

The broadband, coherent nature of narrow-linewidth fiber frequency combs is exploited to measure the full complex spectrum of a molecular gas through multiheterodyne spectroscopy. We measure the absorption and phase shift experienced by each of 155 000 individual frequency-comb lines, spaced by 100 MHz and spanning from 1495 to 1620 nm, after passing through hydrogen cyanide gas. The measured p...

The limitations on scattering amplitudes imposed by causality requirements are deduced from the demand that the commutator of field operators vanish if the operators are taken at points with space-like separations. The problems of the scattering of spin-zero particles by a force center and the scattering of photons by a quantized matter field are discussed. The causality requirements lead in a ...

This text is a part of an unfinished project which deals with the generalized point interaction (GPI) in one dimension. We employ two natural parametrizations, which are known but have not attracted much attention, to express the resolvent of the GPI Hamiltonian as well as its spectral and scattering properties. It is also shown that the GPI yields one of the simplest models in which a non-triv...