Estimation-free spatial-domain image reconstruction of structured illumination microscopy

Structured illumination microscopy(SIM)achieves super-resolution(SR)by modulating the high-frequency information of the sample into the passband of the optical system and subsequent image reconstruction.The traditional Wiener-filtering-based reconstruction algorithm operates in the Fourier domain,it requires prior knowledge of the sinusoidal illumination patterns which makes the time-consuming procedure of parameter estimation to raw datasets necessary,besides,the parameter estimation is sensitive to noise or aberration-induced pattern distortion which leads to reconstruction artifacts.Here,we propose a spatial-domain image reconstruction method that does not require parameter estimation but calculates patterns from raw datasets,and a reconstructed image can be obtained just by calculating the spatial covariance of differential calculated patterns and differential filtered datasets(the notch filtering operation is performed to the raw datasets for attenuating and compensating the optical transfer function(OTF)).Experiments on reconstructing raw datasets including nonbiological,biological,and simulated samples demonstrate that our method has SR capability,high reconstruction speed,and high robustness to aberration and noise.

Correspondence:Wavelength-selective wavefront shaping by metasurface

Precise,wavelength-dependent phase retarding is essential in many fields,such as superresolution imaging,full-color holography,nanomanufacturing,and optical communications.This demand can be achieved by a combination of multiple optical devices but is challenging to implement using a single element.In this paper,we develop a method for metasurface design that allows wavelength-selective wavefront shaping.Specifically,we demonstrate a metasurface that can selectively modulate a beam with a spiral phase at 785 nm and leave another beam unaffected at 590 nm.

Generation of Lommel beams through highly scattering media

Lommel beams have been potential candidates for optical communication and optical manipulation,due to their adjustable symmetry of transverse intensity distribution and continuously variable orbital angular momentum.However,the wavefront of the Lommel beam is scrambled when it transmits through highly scattering media.Here,we explore the construction of Lommel beams through highly scattering media with a transmission matrix-based point spread function engineering method.Experimentally,various Lommel beams with different parameters were generated through a ZnO scattering layer by use of a digital micromirror device.The construction of Lommel beams under high scattering is expected to benefit the optical applications behind highly scattering media.

Creation of cylindrical vector beams through highly anisotropic scattering media with a single scalar transmission matrix calibration

Cylindrical vector(CV)beams have attracted increasing interest due to their particular properties and their applications in optical imaging,optical manipulation,and light-matter interactions.However,it is challenging to construct CV beams through highly anisotropic scattering media(HASM),such as thick biological tissue,posing a barrier to the applications of CV beams that involve HASM.Here,we present a scheme to construct CV beams beyond high scattering that only requires a single scalar transmission matrix(TM)calibration and manipulation of the spatial degrees of freedom of the scalar input field.Assisted by a radial polarization converter(S-waveplate)and a polarizer,the scheme enables one to obtain the correct incident wavefront for the creation of CV beams through HASM with only one single scalar TM calibration.Compared to the existing method,this user-friendly approach is fast and simple in terms of the optical implements and computations.Both radially and azimuthally polarized beams are experimentally constructed through a Zn O scattering layer to demonstrate the viability of the method.Arbitrarily generalized CV beams and arrays of CV beams are also created through the HASM to further prove the flexibility of the method.We believe this work may pave the way for applications of CV beams that involve a highly anisotropic scattering environment.

Edge enhancement of phase objects through complex media by using transmission-matrixbased spiral phase contrast imaging

The wavefront shaping based technique has been introduced to detect the edges of amplitude objects through complex media,but the extraction of the boundary information of invisible phase objects through complex media has not been demonstrated yet.Here,we present a phase contrast imaging technique to overcome the scattering,aiming to achieve the edge detection of the phase object through the complex media.An operator based on the experimentally measured transmission matrix is obtained by numerically adding a spiral phase in the Fourier domain.With the inverse of the filtered transmission matrix,we can directly reconstruct the edge enhanced images for both amplitude object and phase object beyond scattering.Experimentally,both digital and real objects are imaged,and the results verify that isotropic edge detection can be achieved with our technique.Our work could benefit the detection of invisible phase objects through complex media.