Diffractive lenses for chromatic confocal imaging

Abstract

A diffractive zone plate provides a highly linear wavelength-to-depth coding, allowing for nonmechanical depth scanning in a confocal microscope. This chromatic confocal microscope, constructed with 40x and 60x objectives, achieves axial position changes of 55 and 25 mum, respectively, for a wavelength tuning range of 100 nm. The corresponding longitudinal point-spread functions are measured and shown to possess full-width half-maximums of 2.52 and 2.23 mum, respectively. Two-dimensional profiles of a two-phase-level grating and a four-phase-level diffractive structure are given. The performance of the chromatic confocal microscope is consistent with that of the conventional confocal operation of the microscope.

Feasibility Study and Modeling of Components for an Informational Space System Based on a Large Diffractive Membrane

“…Aso, it enables simple elements replication in order to form both spherical and aspherical wavefront sets, making diffractive optic's elements useful for different applications. The majority of studies consider diffractive optical elements either as additional elements for the compensation of aberrations of a refractive imaging system [4,5], or as elements for focusing on a particular area [4][5][6][7][8][9][10][11][12][13][14]. For example, in [6,7] longitudinal intensity distribution for a coherent case is considered, [8] considers the process of a plane wave focus using a Fresnel lens, and [9] researches methods of compensation of DOE chromatic aberration.…”

Chromatic Confocal Microscopy

“…In principle, any dispersive device could be used as the chromatic objective, such as diffractive lenses (Dobson 1997, Lin 1998 or dynamic wavelength tuning systems. However, the quality of the dispersion and the cost of non-conventional objectives rules out their use in commercial systems.…”

Study of the chromatic properties of harmonic diffractive lens

“…Furthermore, they enable the formation of light beams with properties that can not otherwise be obtained by classical optical refractive elements. However, DOE are characterised by significant chromatic aberration, which can have both negative and positive impacts upon the imaging system [1][2][3][4][5][6][7][8][9][10].…”