Comparison between non-modulation four-sided and two-sided pyramid wavefront sensor

Wang, Jianxin; Bai, Fuzhong; Ning, Yu; Huang, Linhai; Wang, Shengqian

doi:10.1364/oe.18.027534

Cited by 12 publications

(8 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…They do not affect the signs of the signals, but their amplitude, as discussed in [15]. The diffraction theory shows that the SPWFS has the same response characteristics as PWFS.…”

Section: Diffraction Theorymentioning

confidence: 89%

See 1 more Smart Citation

Pyramid wavefront sensor using a sequential operation method

et al. 2015

View full text Add to dashboard Cite

The pyramid wavefront sensor is a novel slope wavefront sensor that is similar to the Foucault knife-edge test. In this paper, we describe a sequential operation method that can be realized using a micromirror array. The goal of this paper is to discuss the possibility and analyze the features of the method. Geometrical optics calculations are described first to illustrate the principle of the method. Then, more exact diffraction calculations are provided that illustrate the method being equivalent to the pyramid sensor in principle but with a weak diffraction effect. Numerical simulations are also provided to verify the feasibility of using a nonmodulation method in the closed-loop system.

show abstract

“…They do not affect the signs of the signals, but their amplitude, as discussed in [15]. The diffraction theory shows that the SPWFS has the same response characteristics as PWFS.…”

Section: Diffraction Theorymentioning

confidence: 89%

“…From the conclusions proposed in [15], a wavefront sensor can work correctly in a closed-loop iteration system if the measured signal trend is coincident with the true signal trend, and a nonmodulation PWFS can be used in a closed-loop adaptive optics system.…”

Section: Numerical Simulationmentioning

confidence: 99%

Pyramid wavefront sensor using a sequential operation method

et al. 2015

View full text Add to dashboard Cite

show abstract

“…The behaviour of the Pyramid in the spatial domain has been extensively studied by Vérinaud (2004); Vérinaud et al (2005); Chew et al (2006); Korkiakoski et al (2007); LeDue et al (2009); Quirós-Pacheco et al (2009); Wang et al (2010); Shatokhina et al (2013); Fauvarque et al (2015Fauvarque et al ( , 2017, following the seminal work of Ragazzoni (1996) who builds on the footsteps of Linfoot's Foucault knife-edge diffraction model (Linfoot (1948)).…”

Section: Optical Models Of the Pyramid Wave-front Sensor Using Diffra...mentioning

confidence: 99%

Performance limits of adaptive-optics/high-contrast imagers with pyramid wave-front sensors

Correia,

Fauvarque,

Bond

et al. 2020

Preprint

View full text Add to dashboard Cite

Advanced AO systems will likely utilise Pyramid wave-front sensors (PWFS) over the traditional Shack-Hartmann sensor in the quest for increased sensitivity, peak performance and ultimate contrast. Here, we wish to bring knowledge and quantify the PWFS theoretical limits as a means to highlight its properties and use cases. We explore forward models for the PWFS in the spatial-frequency domain for they prove quite useful since a) they emanate directly from physical-optics (Fourier) diffraction theory; b) provide a straightforward path to meaningful error breakdowns, c) allow for reconstruction algorithms with O(n log(n)) complexity for large-scale systems and d) tie in seamlessly with decoupled (distributed) optimal predictive dynamic control for performance and contrast optimisation. All these aspects are dealt with here. We focus on recent analytical PWFS developments and demonstrate the performance using both analytic and end-to-end simulations. We anchor our estimates with observed on-sky contrast on existing systems and then show very good agreement between analytical and Monte-Carlo estimates for the PWFS. For a potential upgrade of existing high-contrast imagers on 10 m-class telescopes with visible or near-infrared PWFS, we show under median conditions at Paranal a contrast improvement (limited by chromatic and scintillation effects) of 2x-5x by replacing the wave-front sensor alone at large separations close to the AO control radius where aliasing dominates, and factors in excess of 10x by coupling distributed control with the PWFS over most of the AO control region, from small separations starting with the Inner Working Angle of typically 1-2 λ/D to the AO correction edge (here 20 λ/D).

show abstract

“…Usually, the pyramid is a square pyramid, but other configurations have been considered. [2][3][4][5] The desirability of the PyWFS is due to the fact that it is much more sensitive (in terms of performance for a given guide-star magnitude) than the Shack-Hartmann array for low-order modes, and for high-order modes, it is equally sensitive. [6][7][8][9] The PyWFS' current status as the most promising and powerful type of wavefront sensor for AO was achieved with release of the unprecedented results produced by the First Light AO system on the Large Binocular Telescope, which routinely delivers Strehl ratios greater than 0.8 in the H-band.…”

Section: Introductionmentioning

confidence: 99%

Efficient, nonlinear phase estimation with the nonmodulated pyramid wavefront sensor

Frazin

2018

J. Opt. Soc. Am. A

View full text Add to dashboard Cite

The sensitivity of the pyramid wavefront sensor (PyWFS) has made it a popular choice for astronomical adaptive optics (AAO) systems. The PyWFS is at its most sensitive when it is used without modulation of the input beam. In nonmodulated mode, the device is highly nonlinear. Hence, all PyWFS implementations on current AAO systems employ modulation to make the device more linear. The upcoming era of 30-m class telescopes and the demand for ultra-precise wavefront control stemming from science objectives that include direct imaging of exoplanets make using the PyWFS without modulation desirable. This article argues that nonlinear estimation based on Newton's method for nonlinear optimization can be useful for mitigating the effects of nonlinearity in the nonmodulated PyWFS. The proposed approach requires all optical modeling to be pre-computed, which has the advantage of avoiding real-time simulations of beam propagation. Further, the required real-time calculations are amenable to massively parallel computation. Numerical experiments simulate a PyWFS with faces sloped 3.7° to the horizontal, operating at a wavelength of 0.85 μm, and with an index of refraction of 1.45. A singular value analysis shows that the common practice of calculating two "slope" images from the four PyWFS pupil images discards critical information and is unsuitable for the nonmodulated PyWFS simulated here. Instead, this article advocates estimators that use the raw pixel values not only from the four geometrical images of the pupil, but from surrounding pixels as well. The simulations indicate that nonlinear estimation can be effective when the Strehl ratio of the input beam is greater than 0.3, and the improvement relative to linear estimation tends to increase at larger Strehl ratios. At Strehl ratios less than about 0.5, the performances of both the nonlinear and linear estimators are relatively insensitive to noise since they are dominated by nonlinearity error.

show abstract

Comparison between non-modulation four-sided and two-sided pyramid wavefront sensor

Cited by 12 publications

References 27 publications

Pyramid wavefront sensor using a sequential operation method

Pyramid wavefront sensor using a sequential operation method

Performance limits of adaptive-optics/high-contrast imagers with pyramid wave-front sensors

Efficient, nonlinear phase estimation with the nonmodulated pyramid wavefront sensor

Contact Info

Product

Resources

About