A traditional diffractive optic lens uses one diffractive order in which the lens’ optical power is directly proportional to the wavelength of light. Thus, light illumination allows each wavelength to focus at a different distance from the lens. With broadband illumination, the dependence on this strong wavelength in the optical power produces substantial chromatic aberration in the image. For instance, focusing the green image onto a detector leaves the red and blue images out of focus, producing red or blue halos around the focused green image. With white light illumination, a highly chromatically aberrated image with serious color banding is absorbed around edges of objects, which is not acceptable. Multi-order diffractive lenses provide a new degree of freedom in terms of designing broadband and multiplespectral optical system that include elements of diffractive optics. Keep reading to learn more about the features of these lenses and their benefits:
Multi-Order Diffractive (MOD) Lens Features
MOD lenses are designed to bring multiple wavelengths to a common focus with high efficiency. Thus, it can form sharp, clear images in white illumination. With this lens, the different diffractive orders bring various wavelengths to the common focal point. Because the MOD lens is purely diffractive, the lens’ optical power is determined only by choice of the zone radii and depends on the thickness of the lens. Also, as a MOD lens does not haverefractive power, it is not sensitive to changes in the substrate’s curvature.
Benefits of MOD Lenses
MOD lens technology offers high-quality imaging at a low cost. These lenses can be injection molded, transferred directly into the substrate using reactive-ion etching techniques, or replicated onto a glass substrate with the use of a UV-cured optical polymer. These lenses can be used for vision correction, color laser projecting displays, photolithographic alignment systems, light-weight, low-cost infrared imaging, and laser surgery.
MOD lenses provide optical system designers a new element with useful spectral properties. The first-order properties of these lenses enable the design of achromatic and apochromatic diffractive singlets which can be quite useful for applications like color projection displays and hyperspectral imaging. Also, the optical transfer function (OTF) is highly dependent on wavelengths so that wavelength detunings from the design wavelengths cause a reduction in the image contrast. MOD lens can offer high-quality imaging in broadband or multispectral illumination over wide fields of view. Additionally, this particular MOD lens possesses the required characteristics of a high-performance, multi-color laser scans lens and Fourier-transform lens.
