Accounting for Polychromatic Light in Virtual Shack-Hartmann Wavefront Sensing

Virtual Shack-Hartmann wavefront sensing(vSHWS)has some significant advantages and is promising for aberration measurement in the field of biomedical optical imaging.The illumination sources used in vSHWS are almost broadband,but are treated as monochromatic sources(only using center wavelength)in current data processing,which may cause errors.This work proposed a data processing method to take into account the multiple wavelengths of the broadband spectrum,named multiple-wavelength centroid-weighting method.Its feasibility was demonstrated through a series of simulations.A wavefront generated with a set of statistical human ocular aberrations was used as the target wavefront to evaluate the performance of the proposed and current methods.The results showed that their performance was very close when used for the symmetrical,but the wavefront error of the proposed method was much smaller than that of the current method when used for the asymmetrical spectrum,especially for the broader spectrum.These results were also validated by using 20 sets of clinical human ocular aberrations including normal and diseased eyes.The proposed method and the obtained conclusions have important implications for the application of vSHWS.

Single-pixel wavefront sensing via vectorial polarization modulation[Invited]

The Shack–Hartmann wavefront sensor(SHWFS)is commonly used for its high speed and precision in adaptive optics.However,its performance is limited in low light conditions,particularly when observing faint objects in astronomical applications.Instead of a pixelated detector,we present a new approach for wavefront sensing using a single-pixel detector,which is able to code the spatial position of a light spot array into the polarization dimension and decode the polarization state in the polar coordinate.We propose validation experiments with simple and complex wavefront distortions to demonstrate our approach as a promising alternative to traditional SHWFS systems,with potential applications in a wide range of fields.

Target-independent dynamic wavefront sensing method based on distorted grating and deep learning

A real-time wavefront sensing method for arbitrary targets is proposed,which provides an effective way for diversified wavefront sensing application scenarios.By using a distorted grating,the positive and negative defocus images are simultaneously acquired on a single detector.A fine feature,which is independent of the target itself but corresponding to the wavefront aberration,is defined.A lightweight and efficient network combined with an attention mechanism[AM-EffNet]is proposed to establish an accurate mapping between the features and the incident wavefronts.Comparison results show that the proposed method has superior performance compared to other methods and can achieve high-accuracy wavefront sensing in varied target scenes only by using the point target dataset to train the network well.

Application of phase-diverse phase retrieval to wavefront sensing in non-connected complicated pupil optics

Baseline algorithm, as a tool in wavefront sensing （WFS）, incorporates the phase-diverse phase retrieval （PDPR） method with hybrid-unwrapping approach to ensure a unique pupil phase estimate with high WFS accuracy even in the case of high dynamic range aberration, as long as the pupil shape is of a convex set. However, for a complicated pupil, such as that in obstructed pupil optics, the said unwrapping approach would fail owing to the fake values at points located in obstructed areas of the pupil. Thus a modified unwrapping approach that can minimize the negative effects of the obstructed areas is proposed. Simulations have shown the validity of this unwrapping approach when it is embedded in Baseline algorithm.