The Light Sword Optical Element—a New Diffraction Structure with Extended Depth of Focus

Three dimensional analysis of chromatic aberration in diffractive elements with extended depth of focus

“…In [2,12] we find other interesting elements that produce extended depth of focus with reasonable MTF extent, which allow better contrast, but less resolution than axicons. These elements have been called Light Sword Elements (LSOE) and are based in an angular multiplexing of the convergence information and produce a comatic spot that rotates around the z-axis.…”

“…Several configurations are proposed in the bibliography [1][2][3][4][5][6][7][8][9][10]. Some of them are based on single elements [1,2,4,[6][7][8][9]10] while others are based on convenient association of several elements [3,5,8]. Extended depth of focus in a single element is usually achieved by spatial multiplexing of phase information.…”

“…Extended depth of focus in a single element is usually achieved by spatial multiplexing of phase information. We can find elements in which focusing information is codified in radial [9,11] or angular coordinates [2] or even with random localization through the surface of the element [7]. All these elements share the common property that they produce a long and narrow focal segment which allows imaging in a continuous region in the image domain.…”

“…All these elements share the common property that they produce a long and narrow focal segment which allows imaging in a continuous region in the image domain. The effect can be achieved by multiplexing a continuous range of focalization distances in the element, which can be done either with refractive media [1,3,4,10] or by diffractive optical elements (DOEs) [2,6,7,9,12,13]. Among these systems, we are most interested in single diffractive structures, which can be easily implemented in a spatial light modulator (SLM).…”

“…Among these systems, we are most interested in single diffractive structures, which can be easily implemented in a spatial light modulator (SLM). In particular we will focus our work on two particular elements: Light Sword Optical Elements (LSOE) and Fresnel Axicons (FA) Optical properties of these elements are widely known [1][2][3]11,15] and their performance has been optimized in several ways [16][17][18][19].…”