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Optical Components
Published in Christoph Gerhard, Optics Manufacturing, 2018
Optical components are the basis of any optical system and can generally be classified into lenses, prisms, and plates. Lenses are the most important and commonly used optical components and are characterized by the basic surface shape of the optically active surfaces, spherical, aspherical, toric, or cylindrical. All types of lenses are further specified by the lens material and the center thickness, where thin lenses are distinguished from thick lenses. Spherical lenses are further defined by the radii of curvature of the optically active surface whereas aspherical lens surfaces are described by appropriate mathematical functions. Toric lens surfaces feature two different radii of curvature perpendicular to each other, and cylindrical lenses can be described as a segment of cylinder walls.
Optics in Digital Still Cameras
Published in Junichi Nakamura, Image Sensors and Signal Processing for Digital Still Cameras, 2017
Aspherical lenses, as well as correcting the problem of spherical aberration described in Section 2.1.3, are effective in correcting other nonchromatic aberrations. Depending on where the aspherical elements are used, the dampening effect on the respective aberrations differs. An aspherical lens is said to have the effect of two or three spherical lenses, but when minor improvements in performance are taken into account, it is not unusual for them to be even more effective than this.
Optical design of a null test for off-axis three-mirror system based on refractive-diffractive zoom hybrid compensator
Published in Journal of Modern Optics, 2022
Lai Xiaoxiao, Chang Jun, Li Yiting, Ji Zhongye, Cao Jiajing, Li Dongmei
SLM is a programmable wavefront modulation device, which is composed of liquid crystal arrays. By controlling the electric signals loaded in pixels of SLM, the arrangement of liquid crystal molecules is changed to modify the refractive index of liquid crystal pixels. In this manner, the amplitude or phase of the light passing through the SLM will be modulated. In recent years, SLM has been gradually used as dynamic computer-generated hologram for aspheric surface test [11–13]. In 2019, Shuai Xue et al. [14] proposed a method that using a SLM and an aspheric lens which can move axially as hybrid refractive and diffractive variable null (HRDVN) to test free-form surface. However, they only tested a biconic free-form surface, which cannot prove the versatility of the method.
A high-resolution wavefront sensing method to investigate the annular Zernike polynomials behaviour in the indoor convective air turbulence in the presence of a 2D temperature gradient
Published in Journal of Modern Optics, 2021
E. Mohammadi Razi, Saifollah Rasouli, M. Dashti, J. J. Niemela
A schematic diagram of the experimental set up is shown in Figure 1(a). The setup consists of a laser, a pair of telescopes, a heater, a two-channel moiré-based wavefront sensor, a CMOS camera, and a computer. A 50 mW CW laser beam with wavelength 532 nm passes through an aspheric lens before entering the first telescope, a 14 inch Celestron (SchmidtCassegrain).The light beam is expanded and re-collimated after traversing this confocal system. The emerging plane wave then passes through the turbulent medium, and the aberrated wavefront enters through the aperture of the second telescope (Meade 8 inch Lx200 GPS Schmidt-Cassegrain). After the second telescope, the light beam was re-collimated by a 20 cm focal length lens and then split by a beam splitter, with the beams entering a pair of the moiré deflectometers. It is worth mentioning that we have recently used a very simple version of this arrangement without using the wavefront sensor for the study of inhomogeneity and anisotropy of a similar turbulent medium [19].
Zoom projection lens design for small throw ratio and large field of view
Published in Journal of Modern Optics, 2018
Daoping Li, Jihong Zheng, Bo Yang
Optical design difficulties are representative of lateral colour control and distortion correction. The achromatic doublet lens placed behind the stop is useful in controlling the lateral colour. The lens with large dispersion coefficient is placed in the front, and the lens with small dispersion coefficient is placed at the back. The aspheric lens and aspheric mirror are used in distortion correction. In order to meet the requirements of distortion correction, we take two steps to optimize the optical system. Firstly, we use the function of user-defined aberration in Codev software to control the image height in a certain range for each FOV. If not, distortion is difficult to optimize afterwards. Then, we optimize other aberrations so that the optimized system will be stable. In addition, the weight of the field and wavelength also need to be adjusted during the optimization at the same time.