Tunable resonator with a mirror of variable curvature

Belomestnov, P I; Vyazovich, E I; Soloukhin, R. I.; Yakobi, Yu. A.

doi:10.1070/qe1974v003n04abeh005518

Cited by 4 publications

(2 citation statements)

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“…As Fig. 2 tells, Former Soviet Union [18][19][20], France [21][22][23], Germany [24,25], America [26][27][28], Japan [29,30] and China [10,31,32] have done lots of research on VCM for different application purposes and we also make our own contributions to this field as well [12][13][14][15][16]. Among these versatile applications, focus adjusting and zooming are two basic ones.…”

Section: Re-focusmentioning

confidence: 99%

Depth of focus extension of space-borne optical camera through variable curvature mirror

Zhao,

Xie,

Yang

et al. 2023

Optical Design and Testing XIII

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Currently, most space-borne optical cameras have fixed focal length and depth of focus. In this case, the range within which the target can be clearly imaged has been pre-determined before launch. However, the distance of the target to the optical camera might be unknown or change very fast and therefore focus adjustment has to be carried out to obtain clear images. However, no matter which refocusing technique is used, focus adjustment might lag behind the object distance variation and depth of focus extension is a better way. Wave-front coding can be used to extend the depth of focus of incoherent imaging system but the surface profile of the phase mask could not be changed dynamically, which is not flexible for application. In this manuscript, by combing the variable curvature mirror (VCM) and coded imaging technique together, a new depth of focus extension technique is proposed. According to our previous studies, the focal plane could be quickly adjusted by changing the curvature radius of VCM. Compared with the curvature variation speed, the exposure time of the camera is quite long. Therefore, by adjusting the focal plane very fast in a wide range during the exposure through VCM, an equivalent coded optical transfer function having no null frequency points within bandwidth is generated and the image captured is uniformly blurred. After that, with the help of digital restoration, the clear image could be obtained. Because the focal plane could be adjusted through variable curvature mirror in the range of millimeter, the proposed method could be used to obtain clear images with greatly extended depth of focus.

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Section: Re-focusmentioning

confidence: 99%

Depth of focus extension of space-borne optical camera through variable curvature mirror

Zhao,

Xie,

Yang

et al. 2023

Optical Design and Testing XIII

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“…A variable curvature mirror, generated by perimeter bending moments, was developed in a search as an optimal variant for a resonator of an electric discharge CO 2 laser. This was studied using either a germanium exit mirror or metallized mirrors with central apertures of different diameters (Belomestnov et al [5]). Grazing incidence mirrors were actively bent into an ellipsoidal shape to increase the detection efficiency.…”

Section: Introductionmentioning

confidence: 99%

Active Optics—Progress in Modeling of Tulip-like Variable Curvature Mirrors

Lemaitre

Vola

Lanzoni

2023

Optics

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We present new results obtained from the modeling of a tulip-like variable curvature mirror (VCM) in the case of a central force that reacts to its contour. From Nastran finite element analysis, we shows that 3-D optimizations, using non-linear static flexural option, with an appropriate solution sequence, provide an accurate tulip-like VCM thickness distribution. This allows us to take into account boundary conditions, including the thin outer collarette and its link to a rigid ring. Modeling with a quenched stainless steel chromium substrate provides diffraction-limited optical surfaces. Rayleigh’s quarter-wave criterion is performed over a zoom range from flat up to f/3.5 convexity over a 13 mm clear aperture and 10 daN central force. The optical testing results of a prototype tulip-like VCM elaborated from the previous analytic theory, show quasi-diffraction-limited figures for a zoom range up to f/5. The present modeling results should significantly help in the future construction of such VCMs with a zoom range extended up to f/3.5.

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Solving, analyzing, manufacturing, and experimental testing of thickness distribution for a cycloid-like variable curvature mirror

Xie

Wang

et al. 2021

Opt. Express

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A cycloid-like variable curvature mirror (VCM) for zoom-imaging systems was investigated. An analytical-deformation solution to a thin-elastic plate with a cycloid-like thickness distribution and simply supported boundary condition under uniform pressure was found using a small parameter method. The finite-element analysis of the thin-elastic plate and designed VCM showed a good correlation with the analytical solution. The VCM was manufactured and polished to the initial shape with a root mean square (RMS) of 1/80λ. Finally, with air-pressure-based actuation testing under 0.07 MPa, the VCM deforms approximately 36.89 µm and maintains the RMS surface performance of 1/10λ, 1/40λ with and without spherical aberrations, respectively.

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Tunable resonator with a mirror of variable curvature

Cited by 4 publications

References 0 publications

Depth of focus extension of space-borne optical camera through variable curvature mirror

Depth of focus extension of space-borne optical camera through variable curvature mirror

Active Optics—Progress in Modeling of Tulip-like Variable Curvature Mirrors

Solving, analyzing, manufacturing, and experimental testing of thickness distribution for a cycloid-like variable curvature mirror

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