An Improved Equivalent Dipole Moment Source Model Based on Regularization Optimization Method for Near Field-Far Field Conversion

A sparse equivalent source method for near-field acoustic holography.

This study examines a near-field acoustic holography method consisting of a sparse formulation of the equivalent source method, based on the compressive sensing (CS) framework. The method, denoted Compressive-Equivalent Source Method (C-ESM), encourages spatially sparse solutions (based on the superposition of few waves) that are accurate when the acoustic sources are spatially localized. The i...

Near field acoustic holography based on the equivalent source method and pressure-velocity transducers.

The advantage of using the normal component of the particle velocity rather than the sound pressure in the hologram plane as the input of conventional spatial Fourier transform based near field acoustic holography (NAH) and also as the input of the statistically optimized variant of NAH has recently been demonstrated. This paper examines whether there might be a similar advantage in using the p...

An Alternative Spherical near Field to Far Field Transformation

Near-field imaging with far-field data

Using the inverse diffractive grating problem as an example, we demonstrate how a super-resolution can be achieved stably by using far-field data. The idea is to place a slab of a homogeneous medium with a large index of refraction above the grating surface, and more propagating wave modes can be utilized from the far-field data which contributes to the reconstruction resolution. © 2016 Elsevie...

Optical dipole model for photodetection in the near field.

Near-field photodetection optical microscopy (NPOM) is a scanning probe technique that has been developed to perform nanometer-scale optical intensity mapping and spectroscopy. In NPOM a nanometer-scale photodiode detector absorbs power directly as it is scanned in the near field of an illuminated sample surface. A model of photodetection in the near and intermediate fields is presented. A brie...