Optimal Filter Design for Annular Imaging

Abstract

Filters of the type exp(in theta)sgn J(n)(z(o)r) with theta the azimuthal angle and r the radial coordinate in the filter plane, are shown to maximize the energy content in a narrow annular image of radius z(o) with respect to incident energy. The simplest optimal filter, sgnJ(o)(z(o)r), is well approximated by the binary circular phase grating sgn cos(z(o)r - pi/4). The single lobe of the first order image of this filter contains 46% of the incident energy within the half-width 0.4lambdaf/a, centered around the image radins Nlambdaf/(2a), where N approximately z(o)/pi is the number of filter sections.

Efficient generation of a perfect optical vortex by using a phase optical element

“…Fig. 4 shows intensity distributions for the initial light field (5), while the Table 3 shows the computed parameters of this POV. From Fig.…”

“…The element in [4] is closest to the optimal phase filter proposed in our work. Generation of POV is compared by using 1) an amplitude-phase light field described by a Bessel mode of limited radius, 2) by an optimal phase light field, described in [5] and 3) by the phase field generated by using a conical axicon and SPP [2].…”

Diffractive optical elements for capturing and controlled rotation of micro-objects

“…When light passes through the axicon, a Bessel beam of the n-power is formed, J n (r), where  = k cos (υλ) (k -wave number). Information Technology and Nanotechnology (ITNT-2015) In accordance with one work [15], it is provided to generate Bessel beams using the DOE with a transmission function…”

Formation of bessel beams by vortex axicons

“…Такой элемент при топологическом заряде структу-ры 0 очень похож на вихревой аксикон, предложенный в [13]. Визуально отличия видны только в центре эле-мента.…”

“…того, и спиральный бинарный аксикон, и элемент [13] являются частными случаями рассматриваемых ДОЭ. В результате формирование пучков Бесселя одного по-рядка может быть осуществлено с помощью дифракци-онных оптических элементов, имеющих совершенно разную по структуре фазовую функцию, что позволит формировать на оптической оси суперпозиции пучков Бесселя с близкими константами распространения.…”