No Arabic abstract
Fluorescence microscopy is a powerful tool to measure molecular specific information in biological samples. However, most biological tissues are highly heterogeneous because of refractive index (RI) differences and thus degrade the signal-to-noise ratio of fluorescence images. At the same time, RI is an intrinsic optical property of label free biological tissues that quantitatively relates to cell morphology, mass, and stiffness. Conventional imaging techniques measure fluorescence and RI of biological samples separately. Here, we develop a new computational hybrid imaging method based on a multi-slice model of multiple scattering that reconstructs 3D fluorescence and 3D RI from the same dataset of fluorescence images. Our method not only bridges the gap between fluorescence and RI imaging and provides a panoramic view of the biological samples, but also can digitally correct multiple scattering effect of fluorescence images from the reconstructed 3D RI. Computational hybrid imaging opens a unique avenue beyond conventional imaging techniques.
We demonstrate single-pixel imaging in the spectral domain by encoding Fourier probe patterns onto the spectrum of a superluminescent laser diode using a programmable optical filter. As a proof-of-concept, we measure the wavelength-dependent transmission of a Michelson interferometer and a wavelength-division multiplexer. Our results open new perspectives for remote broadband measurements with possible applications in industrial, biological or security applications.
Conventional imaging systems comprise large and expensive optical components which successively mitigate aberrations. Metasurface optics offers a route to miniaturize imaging systems by replacing bulky components with flat and compact implementations. The diffractive nature of these devices, however, induces severe chromatic aberrations and current multi-wavelength and narrowband achromatic metasurfaces cannot support full visible spectum imaging (400-700 nm). We combine principles of both computational imaging and metasurface optics to build a system with a single metalens of NA ~ 0.45 which generates in-focus images under white light illumination. Our metalens exhibits a spectrally invariant point spread function which enables computational reconstruction of captured images with a single digital filter. This work connects computational imaging and metasurface optics and demonstrates the capabilities of combining these disciplines by simultaneously reducing aberrations and downsizing imaging systems with simpler optics.
Multiphoton microscopy (MPM) has gained enormous popularity over the years for its capacity to provide high resolution images from deep within scattering samples1. However, MPM is generally based on single-point laser-focus scanning, which is intrinsically slow. While imaging speeds as fast as video rate have become routine for 2D planar imaging, such speeds have so far been unattainable for 3D volumetric imaging without severely compromising microscope performance. We demonstrate here 3D volumetric (multiplane) imaging at the same speed as 2D planar (single plane) imaging, with minimal compromise in performance. Specifically, multiple planes are acquired by near-instantaneous axial scanning while maintaining 3D micron-scale resolution. Our technique, called reverberation MPM, is well adapted for large-scale imaging in scattering media with low repetition-rate lasers, and can be implemented with conventional MPM as a simple add-on.
We report both sub-diffraction-limited quantum metrology and quantum enhanced spatial resolution for the first time in a biological context. Nanoparticles are tracked with quantum correlated light as they diffuse through an extended region of a living cell in a quantum enhanced photonic force microscope. This allows spatial structure within the cell to be mapped at length scales down to 10 nm. Control experiments in water show a 14% resolution enhancement compared to experiments with coherent light. Our results confirm the longstanding prediction that quantum correlated light can enhance spatial resolution at the nanoscale and in biology. Combined with state-of-the-art quantum light sources, this technique provides a path towards an order of magnitude improvement in resolution over similar classical imaging techniques.
Multispectral cameras capture images in multiple wavelengths in narrow spectral bands. They offer advanced sensing well beyond normal cameras and many single sensor based multispectral cameras have been commercialized aimed at a broad range of applications, such as agroforestry research, medical analysis and so on. However, the existing single sensor based multispectral cameras require accurate alignment to overlay each filter on image sensor pixels, which makes their fabrication very complex, especially when the number of bands is large. This paper demonstrates a new filter technology using a hybrid combination of single plasmonic layer and dielectric layers by computational simulations. A filter mosaic of various bands with narrow spectral width can be achieved with single run manufacturing processes (i.e., exposure, development, deposition and other minor steps), regardless of the number of bands.