Adjustable hybrid diffractive/refractive achromatic lens.
Bottom Line: Inserting fluid volume through a pump system into the clear aperture region alters the membrane curvature and adjusts the refractive lens' focal position.Primary chromatic aberration is remarkably reduced through the coupling of the fluidic and diffractive lenses at selected focal lengths.Potential applications include miniature color imaging systems, medical and ophthalmic devices, or any design that utilizes variable focal length achromats.
Affiliation: College of Optical Sciences, University of Arizona Tucson, Arizona 85721, USA. firstname.lastname@example.orgShow MeSH
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Mentions: Focal lengths of the diffractive and fluidic lenses were first measured separately using the red (HeNe 633 nm), green (HeNe 543 nm), and blue (Argon 488 nm) lasers. We used a linear polarizer with the diffractive lens to account for the polarization effects of the nematic liquid crystal. We can remove the polarizer so the lens works with any randomly polarized light if we add another liquid crystal diffractive lens with an orthogonal buffing direction to the first diffractive lens. As expected, the red light comes into focus first for the diffractive lens since it has negative dispersion. The test results for the two diffractive lenses are shown in Table 2Table 2Diffractive Lens A Results: Measured and Calculated Focal Lengths at the Three Test WavelengthsWavelength (nm)f (555nm) = 1000 mmf (555nm) = 500 mmf (555nm) = 250 mmDataTheoryDataTheoryDataTheory633870876.8435438.4217219.254310151022.1505511.1252255.548811251137.3560568.6281284.3 and 3Table 3Diffractive Lens B Results: Measured and Calculated Focal Lengths at the Three Test WavelengthsWavelength (nm)f (555nm) = 400f (555nm) = 200f (555nm) = 133f (555nm) = 100f (555nm) = 67DataTheoryDataTheoryDataTheoryDataTheoryDataTheory633348350.7174175.3116116.98887.75958.4543405408.5202204.2135136.1102102.16968.1488447454.9225227.5152151.6114113.77675.8. The experimental and theoretical values of focal lengths at the aforementioned three test wavelengths are presented in Table 2 (diffractive lens A) and Table 3 (diffractive lens B). The design wavelength for both lenses is λ = 555 nm, and the design focal lengths (1000 mm for lens A and 250 mm for lens B) as well as additional observed focal lengths developed when these lenses were shunted as is presented at the design wavelength. The focal lengths at the three test wavelengths are calculated using the diffractive lens formula discussed in the introduction, f (λ) = (555/ λ) fd where fd is the design focal length at 555 nm.As an example, the images of three of the focal spots of the diffractive lens B are shown in Fig. 3Fig. 3
Affiliation: College of Optical Sciences, University of Arizona Tucson, Arizona 85721, USA. email@example.com