On the physical realizability of highly focused electromagnetic field distributions

Abstract

A method to evaluate the physical realizability of an arbitrary three-dimensional vectorial field distribution in the focal area is proposed. A parameter that measures the similarity between the designed (target) field and the physically achievable beam is provided. This analysis is carried out within the framework of the closest electromagnetic field to a given vectorial function, and the procedure is applied to two illustrative cases.

Optical encryption in the longitudinal domain of focused fields

“…Nowadays, highly focused beams are present in numerous research areas and technical applications [1][2][3][4][5][6][7][8][9][10]. However, to the best of our knowledge no research has been reported in the field of optical security [11][12][13], using focused fields.…”

Quantitative comparison of self-healing ability between Bessel–Gaussian beam and Airy beam

“…Similarity can be used to quantitatively estimate the difference between beams [21,22]. For example, the difference between closest field and target function has been studied by using similarity [21].…”

“…For example, the difference between closest field and target function has been studied by using similarity [21]. Because self-healing ability of an Airy beam and a Bessel beam has been widely studied due to the flexible applications [4,8,9,16], in this paper the comparison of the self-healing ability between Airy beam and Bessel beam has been established.…”

Synthesis of highly focused fields with circular polarization at any transverse plane

“…Beam shaping in the focal area of a high numerical aperture objective lens requires a careful design of the input wavefront. In particular, full control of the complex amplitude and polarization distributions of the paraxial input field is required to generate focused fields adapted to the requirements of a specific problem [10]. Interestingly, several authors described inverse methods to find the pupil function from a predetermined field distribution in the focal area [11,12].…”