Optical volumetric projection for fast 3D imaging through circularly symmetric pupil engineering

Abstract

Monitoring and manipulating neuronal activities with optical microscopy desires a method where light can be focused or projected over a long axial range so that large brain tissues (>100 [Formula: see text] thick) can be simultaneously imaged, and specific brain regions can be optogenetically stimulated without the need for slow optical refocusing. However, the micron-scale resolution required in neuronal imaging yields a depth of field of less than 10 [Formula: see text] in conventional imaging systems. We propose to use a circularly symmetric phase mask to extend the depth of field. A numerical study shows that our method maintains both the peak and the shape of the point spread function vs the axial position better than current methods. Imaging of a 3D bead suspension and sparsely labelled thick brain tissue confirms the feasibility of the system for fast volumetric imaging.

Full-color and white circularly polarized luminescence from CdSe/ZnS quantum dots by chiral templates of cellulose nanocrystals

“…On the other hand, white CPL has attracted much attention recently due to its potential applications and plenty of studies have been focused on this area. [41][42][43][44][45][46] However, most of these methods gave very low chiral signals, where the CPL dissymmetry factors |g lum | were on the order of 10 À4 -10 À3 . [44][45][46] As discussed above, we have demonstrated that the CNC provides an excellent chiral template for fluorescent materials.…”

“…[32][33][34][35][36][37][38][39][40] On the other hand, white CPL has attracted much attention recently. [41][42][43] However, most white CPLs achieved by chiral luminophores had very low |g lum |, on the order of 10 À4 -10 À3 . [44][45][46] CPLs based on the CNC chiral templates, however, were limited to narrowband so far.…”

2.5D Microscopy: Fast, High-Throughput Imaging via Volumetric Projection for Quantitative Subcellular Analysis

“…We are mainly interested in imaging mammalian cells whose thickness is ∼4–6 μm via a single-shot volumetric projection without serial z -scanning. Among various approaches for EDOF, a circularly symmetric phase function using controlled spherical aberration and defocus , attracted our attention because (i) the intensity of the PSF along the optical axis shows excellent uniformity, unlike other methods showing either a rapid oscillation or a broad Gaussian response that makes it challenging to do quantitative intensity analysis, (ii) the lateral intensity of the PSF is circularly symmetric as contrasted with a cubic phase mask, and (iii) a phase function ensures high transmission efficiency, unlike an amplitude filter . Particularly, we adopted a binary phase function that has shown an EDOF over a certain distance with a relatively sharp focus and well-preserved circularly symmetric intensity distribution around the focal region.…”

“…We introduced circularly symmetric aberration functions at the back focal plane (BFP) of the objective lens to achieve an EDOF. These circularly symmetric phase functions, that is, a combination of spherical aberration (P SA ) and defocusing terms (P DF ), named quartic phase mask 29,31 can be written as…”

“…We introduced circularly symmetric aberration functions at the back focal plane (BFP) of the objective lens to achieve an EDOF. These circularly symmetric phase functions, that is, a combination of spherical aberration ( P SA ) and defocusing terms ( P DF ), named quartic phase mask , can be written as where ρ is the normalized radial coordinate with respect to the maximum radius of the pupil aperture, γ represents the strength of the spherical aberration and determines the extension of axial PSF, and ψ is a parameter to control the position of the focus plane. Then a binarization of the circularly symmetric phase function was induced to convert the continuous phase distribution to a binary phase pattern with only phase 0 and π; otherwise, it yielded an elongated PSF with rapid axial intensity oscillations with a focal shift compared to the original position.…”