Development of adaptive mirror for CO 2 laser

Okada, Takeshi; Ebata, Keiji; Shiozaki, Manabu; Kyotani, Tatuya; Tsuboi, Akihiko; Sawada, Minoru; Fukushima, Hirotaka

doi:10.1117/12.377060

Cited by 5 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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“…It is, however, rather obvious that not all AO applications have similar needs, and in particular that in some cases systems simpler than the astronomical ones can be realized. For example, in some cases there is no need to have the real time information about the aberrated wavefront: either because the aberration variation is slow [22] or because there is a specific phase which remains for a limited amount of time, as for example when correcting low order ocular aberrations "eyeglass prescription"for patient in ophthalmic diagnostics, or in optical devices in which the environmental conditions are not initially defined but the system remains stable in time [23][24][25]. In all these cases it can be convenient to have a simpler AO system, able to correct only the slow variations of the wavefront aberrations.…”

Section: Introductionmentioning

confidence: 99%

Devices and Techniques for Sensorless Adaptive Optics

Bonora¹,

Zawadzki²,

Naletto³

et al. 2012

Adaptive Optics Progress

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Additional information is available at the end of the chapter http://dx.doi.org/10.5772/53550 . IntroductionMinimizinμ the aberrations is the basic concern oλ all the optical system desiμners. For this purpose, a larμe amount oλ work has been carried out and plenty oλ literature can be λound on the subject. Until the last twenty years, the larμe majority oλ the optical desiμn was related to static optical systems, where several opto-mechanical parameters, such as reλractive index, shape, curvatures, etc. are slowly time dependent. In these systems, simple mechanisms can be adopted to chanμe the relative position oλ one or more optical elements λor example, the secondary mirror oλ many astronomical telescopes , or sliμhtly modiλy their shape and curvature as in some synchrotron beamlines, where some optical surλaces are mechanically bent to compensate deλocusinμ. In the last years, a new type oλ optical systems, that we may call dynamical, have heavily occupied the interest oλ optical desiμners, openinμ the possibility oλ workinμ also in situations where the system environment varies rather quickly with time, either in a controlled or not-controlled way. For this class oλ optical systems adaptive optics "O with a closed loop control system has to be implemented. The correction oλ dynamical systems was predicted by "abcock in the [ ] and, then, the λirst prototypes were realized in the early s with the purpose oλ satellite surveillance and launchinμ hiμh power laser beams trouμh the atmosphere [ ]. The most known scientiλic applications oλ closed loop correction by means oλ "O is the acquisition oλ astronomical imaμes in μround-based telescopes [ ] and in-vivo imaμinμ oλ cone photoreceptor mosaic by "O enhanced Fundus Cameras [ ]. In astronomy, to remove the so called seeinμ eλλect, the star liμht twinklinμ due to local dynamic variations oλ the atmospheric density in the air column above the telescope, it is necessary to have the real time knowledμe oλ the waveλront oλ the observed object. This can be realized, λor instance, by means oλ a Shack-Hartmann waveλront sensinμ device coupled to a dedicated λast alμorithm which returns the mathematical description oλ the waveλront aberration, typically throuμh a Zernike series decompo-

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No wavefront sensor adaptive optics system for compensation of primary aberrations by software analysis of a point source image 2 Tests

et al. 2007

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The description of an adaptive optics (AO) system with no wavefront sensor to correct primary aberrations is presented. This system is based on closed loop software that iteratively analyzes a point source target image on the instrument focal plane and suitably modifies the AO device. The performed tests with a pull-only deformable mirror (DM) have shown that the system works very well, reaching an optimal focusing condition in a few seconds using standard components. Such a system can be conveniently applied in all the fields in which a not very fast optical adaptation is acceptable.

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Development of adaptive mirror for CO 2 laser

Cited by 5 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

Devices and Techniques for Sensorless Adaptive Optics

No wavefront sensor adaptive optics system for compensation of primary aberrations by software analysis of a point source image 2 Tests

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