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Aspheric surfaces are widely used in advanced optical instruments. Measuring the aspheric surface parameters (ASPs) with high accuracy is vital for manufacturing and aligning optical aspheric surfaces. This paper provides a review of various techniques for measuring ASPs and discusses the advantages/disadvantages of these approaches. The aim of this review is to contribute to advancements in the fabrication and testing of aspheric optical elements and their practical applications in diverse fields.

The position accuracy of the polishing tool affects the surface quality of the polished aspheric surface. The contact deformation among the polishing tool, abrasives, and aspheric part can cause a displacement, which, in turn, will cause a position error of the polishing tool, which will lead to a significant change in the polishing force. In order to resolve this error, this paper proposed a method of normal displacement compensation for a computer numerical controlled (CNC) polishing system by controlling the polishing force. Firstly, the coupling principle between the polishing force and the position of the polishing tool is expounded, and the relationship between normal displacement and deformation is analyzed. Based on Hertz’s theory, a model of normal displacement is established. Then, on the basis of the decoupled polishing system developed, a normal displacement compensation method was proposed. Finally, a group of comparative experiments was carried out to verify the effectiveness of the proposed method. Compared with no displacement compensation, when the part was polished with the normal displacement compensation method, the value of roughness decreased from 0.4 µm to 0.21 µm, and the unevenness coefficient of surface roughness decreased from 112.5% to 19%. The experimental results show that the polishing quality is improved greatly, and the aspheric surfaces can be polished more uniformly with the method proposed in this paper.

Semiconductor near-infrared lasers have been widely used in lidar systems. However, various source types have different shapes and divergence angles, causing more difficulties for long-distance detection. In this paper, an optical collimation system is designed for a long-range lidar system with a shaped laser source (the wavelength is 905 nm, the emitted spot size is 50 µm long by 10 µm wide, and the divergence angles are 33°and 15°, respectively, which are unconventional). On the basis of the traditional method of aspheric lens setting, a pair of asymmetric aspherical lenses were designed using an extended polynomial. The simulation results show that the spot shapes are all close to circular from 100 mm to 30 m and the spot size always remains the same value. The corrected optical system is put into the designed lidar system for verification. It results show that the average divergence angles in the long and short axis directions are 0.06°and 0.07°, which satisfy the project requirements. This optical system designed provides a collimation scheme and expands the application of vehicle-mounted lidar in the field of long-range detection.

To obtain a continuous range of clear vision for pseudophakic eyes, a design of intraocular lens (IOL) with extended depth of focus (EDoF) was proposed. The IOL was optimized with a multi-configuration approach based on a pseudophakic eye model and the optical performances of the designed IOL were analyzed. The modulation transfer function (MTF) values remain above 0.2 at 50 lp/mm for object distance ranging from 0.35 m to infinity in both photopic vision and mesopic vision over a field of 4°. The optical performances remain stable when the pupil diameter changes from 2.25 mm to 5 mm. Besides, the presented theoretical analyses show the designed IOL has good optical performances for polychromatic light and corneal asphericity. The above shows that the IOL exhibits an excellent ability for pseudophakic eyes to see the object in a continuous range of distance.

The aspheric surface is a commonly used method to improve the imaging quality of the fisheye lens, but it is difficult to determine the position and initial value. Based on the wave aberration theory of the plane-symmetric optical system, a method of using an aspheric surface to design a fisheye lens is proposed, which can quickly determine the appropriate aspheric surface to improve the imaging performance. First, the wave aberration of each optical surface of the fisheye lens is calculated and its aberration characteristics are analyzed. Then, a numerical evaluation function is reported based on the aberration distribution of the fisheye lens on the image plane. According to the functional relationship between the evaluation function and the aspheric coefficient, the position of the aspheric surface and the initial value of the aspheric coefficient can be calculated. Finally, the adaptive and normalized real-coded genetic algorithm is used as the evaluation function to optimize the fisheye lens using an aspheric surface. The proposed method can provide an effective solution for designing a fisheye lens using an aspheric surface.

An in-situ measurement device combining contact probe and capacitive displacement sensor is developed. An aspherical measurement and compensation machining software is also developed. The single point diamond ultra precision cutting experiments for C3604 brass spherical and aspherical surface are carried out. The in-situ measurement and compensation machining experiments are also carried out. After compensation machining, the spherical surface form accuracy PV reaches 231.4 nm, and the aspheric surface form accuracy PV reaches 206.3 nm. Compared with the off-line measurement results, the difference between the results is 3.0 nm, 7.0 nm respectively, the measuring accuracy of the in-situ measurement system and the validity of compensation machining are verified.

A method for designing double aspheric lenses enabling minimal Fresnel losses in the class of stigmatic lenses is considered. Minimization of the Fresnel losses is provided by ensuring equal ray-deviation angles on both aspheric surfaces of the lens. The design of the lens is reduced to the integration of an explicit ordinary differential equation. Simple analytical approximations for the lens profiles are also presented.

With the continuous development of cataract surgery and intraocular lens(IOL), the evaluation of visual quality after IOL implantation has become a research hotspot, and aberration is an important factor that affecting visual quality. After more than 60y of development, IOL has made great improvement in optical design. Due to the fact that conventional spherical IOL has a positive spherical aberration and cannot correct the positive spherical aberration existing in the normal human cornea, it is improved to an aspherical IOL having a negative spherical aberration and a zero spherical aberration. The former can correct the cornea positive spherical aberration, improve the contrast sensitivity and improve visual quality. However, if the optical position does not match, the formation of other higher-order aberrations will have greater impact on visual effects. Although the latter is well tolerated to tilt and decentration, it still cannot compensate for the positive aberration from the cornea. The advent of the non-constant aberration IOL provides a new way for cataract surgeons to solve this problem. In this paper, the concept of aberration, the design principle and advantages and disadvantages of different kinds of aspheric IOL, as well as the observation of clinical application effect of non-constant aberration aspheric IOL are discussed.

Elliptical elements are essential optical surfaces for modifying optical systems. For polishing the whole elliptical surface using doughnut-shaped MCF polishing tool with variable tilt angle, an experimental investigation was conducted in this work. Firstly, a flat workpiece was polished to determine the polishing feasibility. It was found that the middle portion of the polishing tool had optimal ability to remove materials, and the surface roughness Sa at the material removal peak was changed from 134 nm to 17.5 nm within 50 min of polishing. A smoother surface could be obtained using MCF2 slurry and MCF3 slurry, but the use of MCF1 slurry resulted in a rough surface. Then, the effects of working gap h, revolution speed of MCF polishing tool and polishing time on the polishing results were tested to study the polishing characteristics. Sa 9.6 nm and glossiness 278 Gu were obtained, and form error improved from 2.3 μm to 1.3 μm. Finally, the MCF polishing tool was dried to observe the microstructure of the MCF polishing tool after polishing. Abrasive particles were distributed evenly after polishing. It was seen that the abrasive particles were grabbed by the ferric clusters, and the α-celluloses were interleaved between the clusters.

The non-null testing methods have the potential to allow measurement of aspheric surfaces with large departures from a reference sphere. In a non-null configuration, the ray will return along a different path and interfere with a different reference ray. This difference in “mapping” between the test and reference rays creates an additional optical path difference (OPD) contribution, which causes test part errors to be mapped to the wrong location. To correct the mapping errors in non-null test of aspheric surface, correction method are proposed by ray trace and wave-front analysis. Experiments are carried out to illustrate the effectiveness of this approach. The methods can work well, despite large deviation between the theoretic value of the aspheric and the reference wave-front.