Control of chromatic focal shift through wave-front coding

Abstract

Control of chromatic aberration through purely optical means is well known. We present a novel, to our knowledge, optical-digital method of controlling chromatic aberration. The optical-digital system, which incorporates a cubic phase-modulation (CPM) plate in the optical system and postprocessing of the detected image, effectively reduces a system's sensitivity to misfocus in general or axial (longitudinal) chromatic aberration, in particular. A fully achromatic imaging system (one that is corrected for a continuous range of wavelengths) can be achieved by initial optimization of the optical system for all aberrations except chromatic aberration. The chromatic aberration is corrected by the inclusion of the CPM plate and postprocessing.

Ultrathin four-reflection imager

“…In this arrangement, the addition of planar low-power surface-relief diffractive elements fabricated with SPDT can be used to correct the chromatic aberrations incurred from the airdielectric refractions. To help correct the chromatic focal shift present in our current four-reflection imager design, we show in Section 4 simulated and experimental results for the application of PPE to help correct the axial color aberration described earlier by increasing the imaging system's defocus tolerance [15].…”

Dual-band infrared optical imaging system design by wavefront coding

“…The formed images, although insensitive to misfocus aberrations, are not sharp and clear. Signal processing of the formed image is required to produce final clear images [8][9][10][11][12] .…”

The application of wavefront coding in the infrared optical system in the tokomak fusion reaction

“…The significant advantage of this optical system is that the depth of field can be extended without reducing the pupil. In addition to expanding the depth of field, wavefront coding system can also inhibit some aberrations, just like spherical, field curvature and dispersive [2,3], which are caused by defocus.Tokamak was first proposed by Soviet scientists. And in the fifty years, as the application of superconductivity, tokamak made great progress.…”