The nodal lines correspond to neutral fibers in a mechanical model and enable the vectored actuation of a tunable elastomeric lens to address specific wavefront aberrations independently from others as long as their symmetries match. Straight nodal lines prevent crosstalk between actuation axes. 8Īn additional important property of Zernike polynomials is the presence of nodal lines, which come in two types: straight and circular. This actuation concept is analogous to that of the mammalian eye, in which the ciliary muscle applies a radial force to the crystal lens via the zonular fibers. The Poisson’s ratio of PDMS rubbers is approximately 0.5, 7 and due to conservation of the lens volume, the radius of curvature decreases for increasing tensile strain and thus the focal length increases. Application of an outwardly oriented force in the plane of the lens then results in strain-induced deformation. In the unstrained, relaxed state, the resulting lens yields a focal length of 32.6 mm for a refractive index of n PDMS=1.41, 4 which corresponds to a numeric aperture of NA=0.24 ( f#=2.0, free aperture, a 0=16 mm, diameter, d=20 mm).Īs shown in Figure 1, eight mechanical anchors were embedded in opposing pairs at the periphery of the lens. 3 Using the same approach, an equiconvex lens with identical radii of curvature ( =25.84 mm) was fabricated using a flexible, transparent elastomer (PDMS, SE 1740 Dow Corning Corp., Midland, MI, USA). The use of deformable elastomers for realizing strain-tunable lenses has been shown previously. As a result, the microlens is not only tunable in focal length, but the concomitant aberrations can be increased or decreased at will. We show here that application of azimuthally varying strain to a deformable elastomer lens can result in controlled variation of aberrations, particularly astigmatism. 6 Here two perpendicularly oriented cylindrical lenses provide variable astigmatism, whose total focus is compensated with a rotational symmetric membrane lens. A more versatile approach with a combination of several membrane lenses was pursued by Marks et al. were able to tune astigmatism along one axis, while the other axis remains fixed. 5 By choosing an anisotropic heater structure, Lee et al. 4 presented a tunable composite lens, one part being a fixed focal length lens made of poly(methylmetacrylate) and the tunable part using a membrane with a poly(dimethylsiloxane) (PDMS) elastomer as a filling the surface profiles showed an inherent astigmatism.Īlternatively, singlet polymer lenses with thermal actuation have been reported by Lee et al. A number of other tunable devices have considered the astigmatism. To date, strain has only been applied symmetrically around these tunable elastomeric lenses, such that only refractive power (focal length), but not other optical properties, have been tuned. 1 One approach with considerable potential is the mechanical deformation of microlenses entirely made of flexible elastomers: by controlled application of radial strain, resulting in a change in lens curvature, it has been shown that the focal length can be tuned over a considerable range. | _zernikelist_ = ['Z00 Piston or Bias', 'Z11 x Tilt', 'Z11 y Tilt', '.A broad spectrum of tunable micro-optical components using a wide variety of physical effects has been proposed and demonstrated. | Data and other attributes defined here: | list of weak references to the object (if defined) | dictionary for instance variables (if defined) | Return a 3D Zernike Polynomials surface figure | zernikesurface(self, label=True, zlim=, matrix=False) | Return a 2D Zernike Polynomials map figure | Return a 1D cutoff through x and y axis of a 3D | peak value of the corresponding Seidel aberration term, | Ap is the piston aberration,coefficients Ai represent the | Remove tilt, it is mainly caused by system tilt, not aberration | Remove piston, it is just same value for whole aberration map | ? Is high order coma also caused by misalinement ? | Remove coma, most of coma is caused by misalinement | z: exit pupil to image plane distance(m) | Return the point spread function of a wavefront described by | z: Distance from exit pupil to image plane | Return a set of Zernike Polynomials Coefficient Help on class Coefficient in module opticspy.zernike:
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