Characterization of deep sub-wavelength nanowells by imaging the photon state scattering spectra

Abstract

Optical-matter interactions and photon scattering in a sub-wavelength space are of great interest in many applications, such as nanopore-based gene sequencing and molecule characterization. Previous studies show that spatial distribution features of the scattering photon states are highly sensitive to the dielectric and structural properties of the nanopore array and matter contained on or within them, as a result of the complex optical-matter interaction in a confined system. In this paper, we report a method for shape characterization of subwavelength nanowells using photon state spatial distribution spectra in the scattering near field. Far-field parametric images of the near-field optical scattering from sub-wavelength nanowell arrays on a SiN substrate were obtained experimentally. Finite-difference time-domain simulations were used to interpret the experimental results. The rich features of the parametric images originating from the interaction of the photons and the nanowells were analyzed to recover the size of the nanowells. Experiments on nanoholes modified with Shp2 proteins were also performed. Results show that the scattering distribution of modified nanoholes exhibits significant differences compared to empty nanoholes. This work highlights the potential of utilizing the photon status scattering of nanowells for molecular characterization or other virus detection applications.

Characterization of near-field emission and structure of an SLD by polarization parametric indirect microscopic imaging

“…PIMI is a polarization imaging technique for visualization of end-face in semiconductor light-emitting chips, which can reflect the photon state distribution of the polarization-modulated light beam after its interaction with end-face structure [13,15]. Since different material layers Comparisons of intensity profiles between TM and sin δ images, here sin δ is easy to observe complete SLD spots as well as asymmetries, especially its spot boundaries.…”

“…Such multi-dimensional images provide additional insight to resolve the geometrical features of the measured nanostructures, enabling PIMI an outstanding and non-invasive tool for label-free optical imaging with high resolution and simple setup [13]. So far, this method has been successfully employed to analyze the structural characteristics such as dimensions and shapes of graphene layers, nanoparticles, and other dielectric or metallic samples [10,[13][14][15][16][17], providing a solid basis for us to improve the detection ability to the end face in the semiconductor light-emitting devices. Due to the diverse reflection and scattering characteristics of the different material layers and the possible impurities in the end face, when a beam of polarized light strikes the end face, multilayers will interact with the incident photons states and generate different responses, and then structural features will be encoded to the scattering signals.…”

Signal denoising of viral particle in wide-field photon scattering parametric images using deep learning

“…PIMI provides a series of parametric images which reflects the detailed nanoscale properties of the sample which is unable to be uncovered in conventional microscopes. Therefore, it has been effectively applied for investigating the morphological and structural features of graphene layers [1], nano-particles [2] and nanopores [11]. PIMI system has been proved to be able to obtain information about nanostructures, making it possible to screen for the early infection by detection of viral particles with an optical system.…”

Gold-viral particle identification by deep learning in wide-field photon scattering parametric images

“…PIMI obtains anisotropic nanoscale structural information about the sample by utilizing a polarization modulated illumination scheme and analyzing the far-field variation of polarization states of the scattered photons. By fitting and filtering the intensity variations of the image pixels, a set of parametric images, such as sin(δ) and Φ images, can be obtained in which the spatial resolution is greatly enhanced compared to conventional optical microscopy, enabling the collection of features smaller than 100 nm [18]. As shown in Fig.…”

“…In our previous work, we have investigated the ability of polarization indirect microscopic imaging (PIMI) to resolve nano-features and molecular structures from the spatial polarization status distribution in the nano scattering field [15][16][17][18]. We also demonstrated that anisotropy in nanostructures can be identified from the scattered photon distribution [19,20].…”