Lisa V. Poulikakos

In fluid flow imaging, intensity gradients are a good measure of spatial variations in scalar properties, which play an important role in controlling transport processes. However, current flow imaging techniques exhibit system-limited spatial resolutions, thus inhibiting the ability to accurately detect intensity gradients. To address this challenge, we present a method and system, inspired by Structured Illumination Microscopy (SIM), which can be implemented in dynamic flow imaging to enhance pixel resolution and, thereby, the estimation of scalar gradients. We utilize sub-pixel-scale patterned light matching the system pixel scale and multi-frame imaging that creates quasi-static images over four frames, with scalability for high-speed imaging. These multi-frame images are then processed using a bespoke recombination algorithm that produces a new image with twice the pixel resolution compared to the original images. The sub-pixel spatial-resolution enhancement capabilities are shown with static images and dynamic fluid flow, for which enhancement in the flow gradient is demonstrated.

Supplemental Information

Supplemental Information

Supplemental Information

In fluid flow imaging, intensity gradients are a good measure of spatial variations in scalar properties, which play an important role in controlling transport processes. However, current flow imaging techniques exhibit system-limited spatial resolutions, thus inhibiting the ability to accurately detect intensity gradients. To address this challenge, we present a method and system, inspired by Structured Illumination Microscopy (SIM), which can be implemented in dynamic flow imaging to enhance pixel resolution and, thereby, the estimation of scalar gradients. We utilize sub-pixel-scale patterned light matching the system pixel scale and multi-frame imaging that creates quasi-static images over four frames, with scalability for high-speed imaging. These multi-frame images are then processed using a bespoke recombination algorithm that produces a new image with twice the pixel resolution compared to the original images. The sub-pixel spatial-resolution enhancement capabilities are shown with static images and dynamic fluid flow, for which enhancement in the flow gradient is demonstrated.

In fluid flow imaging, intensity gradients are a good measure of spatial variations in scalar properties, which play an important role in controlling transport processes. However, current flow imaging techniques exhibit system-limited spatial resolutions, thus inhibiting the ability to accurately detect intensity gradients. To address this challenge, we present a method and system, inspired by Structured Illumination Microscopy (SIM), which can be implemented in dynamic flow imaging to enhance pixel resolution and, thereby, the estimation of scalar gradients. We utilize sub-pixel-scale patterned light matching the system pixel scale and multi-frame imaging that creates quasi-static images over four frames, with scalability for high-speed imaging. These multi-frame images are then processed using a bespoke recombination algorithm that produces a new image with twice the pixel resolution compared to the original images. The sub-pixel spatial-resolution enhancement capabilities are shown with static images and dynamic fluid flow, for which enhancement in the flow gradient is demonstrated.

Supplemental Information

Supplemental Information

In fluid flow imaging, intensity gradients are a good measure of spatial variations in scalar properties, which play an important role in controlling transport processes. However, current flow imaging techniques exhibit system-limited spatial resolutions, thus inhibiting the ability to accurately detect intensity gradients. To address this challenge, we present a method and system, inspired by Structured Illumination Microscopy (SIM), which can be implemented in dynamic flow imaging to enhance pixel resolution and, thereby, the estimation of scalar gradients. We utilize sub-pixel-scale patterned light matching the system pixel scale and multi-frame imaging that creates quasi-static images over four frames, with scalability for high-speed imaging. These multi-frame images are then processed using a bespoke recombination algorithm that produces a new image with twice the pixel resolution compared to the original images. The sub-pixel spatial-resolution enhancement capabilities are shown with static images and dynamic fluid flow, for which enhancement in the flow gradient is demonstrated.

In fluid flow imaging, intensity gradients are a good measure of spatial variations in scalar properties, which play an important role in controlling transport processes. However, current flow imaging techniques exhibit system-limited spatial resolutions, thus inhibiting the ability to accurately detect intensity gradients. To address this challenge, we present a method and system, inspired by Structured Illumination Microscopy (SIM), which can be implemented in dynamic flow imaging to enhance pixel resolution and, thereby, the estimation of scalar gradients. We utilize sub-pixel-scale patterned light matching the system pixel scale and multi-frame imaging that creates quasi-static images over four frames, with scalability for high-speed imaging. These multi-frame images are then processed using a bespoke recombination algorithm that produces a new image with twice the pixel resolution compared to the original images. The sub-pixel spatial-resolution enhancement capabilities are shown with static images and dynamic fluid flow, for which enhancement in the flow gradient is demonstrated.

The arrangement of fibrous tissue microstructure is an indicator of the progression of many fatal and ever-occurring diseases. Common techniques for visualizing this property include biochemical stains that provide subjective information or complex and costly optics that are capable of visualizing these fibers at high resolutions. Polarized light microscopy presents an avenue in which the inherent birefringence of the extracellular fibers can be leveraged to observe their formation in a non-invasive and low-cost manner. However, most biological fibers possess relatively weak birefringence. Here we leverage the optical anisotropy of the Morpho butterfly wing and introduce Morpho-Enhanced Polarized Light Microscopy (MorE-PoL), a stain-free approach to imaging histological samples. We quantitatively assessed the anisotropic behavior of these histological tissue sections interfaced with the Morpho butterfly wing. The promising diagnostic properties of this stain-free imaging platform introduces a new method of diagnostic imaging for rapid, precise, and low-cost tissue diagnostics.

Photonic materials with sub-wavelength features have enabled unique light-matter interactions; however, fabrication methods face challenges in achieving high-resolution features and tunable structures at scale. In this work, laser-processing of photonic materials is studied. First, multilayered gratings are fabricated using two-photon absorption lithography for polarization-sensitive structural colors. By varying the grating design and light polarization conditions, the transmitted structural color response is analyzed. Next, we investigate the laser focusing beyond Abbe’s diffraction limit using ultrasmooth plasmonic pyramidal arrays. The electric field enhancement due to nanoscale curvature at the apex is characterized, and pyramidal structures of different metals are integrated into a high-precision substrate patterning setup. Overall, this work showcases high-resolution feature size and structural control in laser-based techniques, offering insights into novel micro- and nanofabrication techniques.

Imaging science is a critical enabler of revolutionary scientific advances across disciplines. However, current imaging technologies face prohibitive trade-offs in resolution, penetration depth and experimental complexity. Here, we introduce new classes of micro- and nanostructured photonic surfaces which scale down and enhance light-matter interactions, to overcome existing challenges in imaging science in a miniaturized, on-chip format. We introduce “acoustoplasmonic metasurfaces” to enable tunable acoustic wavefront shaping with polarized light. The proposed acoustoplasmonic metasurfaces merge the physics of light and sound in previously unexplored ways, opening new avenues to harness wave-matter interactions. Future applications of acoustoplasmonic metasurfaces include on-chip imaging with simultaneously high spatial resolution and penetration depth, which can enable societally relevant applications ranging from biomedicine to industrial materials, to environmental science.

Plasmonic metasurfaces describe a class of optical metasurfaces composed of resonant plasmonic nanoparticles, which exhibit strong concentration, scattering, and absorption of electromagnetic energy at subwavelength scales. While their absorptive properties can be a hindrance in all-optical applications, they are advantageous for electromagnetic-to-mechanical energy conversion. This phenomenon is leveraged in acoustoplasmonic metasurfaces, in which incident light excites an acoustic wave. We analytically and numerically examine this acoustic wavefront actuation, which involves the coupling of optical, thermoelastic, and acoustic mechanisms for gold nanospheres. We furthermore demonstrate how nanoparticle anisotropy and relative nanoparticle arrangement enables polarization-tunable acoustic wavefront shaping. The foundational understanding of these mechanisms enables rationally designed wavefront shaping via optimization algorithms. We finally turn our attention towards the experimental realization of these analytical and numerical studies, namely tunable acoustic wavefront actuation using polarized light.

Optical and acoustic metasurfaces are two-dimensional arrays of subwavelength elements that locally modulate or phase shift incident waves. Acoustoplasmonic metasurfaces combine the physics of light and sound, producing acoustic wavefronts in response to optical stimuli. Herein, we present a computational inverse acoustoplasmonic metasurface design algorithm for desired optically generated acoustic wave fields. We consider gold nanoparticles producing spherical acoustic waves in water, and the resulting acoustic wave propagation along the plane containing the nanoparticle array. We demonstrate how our algorithm can be used to design metasurfaces that can be used to achieve complex acoustic wave fields. This includes the design of a single metasurface that produces acoustic wave fields mimicking two different Morse code patterns upon stimulation with two orthogonal polarization states of light. This work provides a tool for the design of complex optically generated acoustic wavefronts, enabling functionality beyond what would be achievable with off-optical-resonance optoacoustic excitation.

Metasurfaces have pioneered significant improvements in sensing technology by tailoring strong optical responses to weak signals. When designed with narrow-bandwidth, guided-mode resonances, metasurfaces can exhibit high sensitivity to changes in the intensity or polarization of light. Leveraging this to quantify structural alignment in fibrous materials unveils an alternative to destructive characterization methods. This work introduces metasurface-enhanced polymeric alignment detection (Meta-PAD), which employs polarization-tunable, guided-mode-resonant colorimetric metasurfaces to characterize molecular and bulk alignment of poly(ε-caprolactone) (PCL) nanofibers in a far-field configuration. PCL nanofibers drawn at 0%, 400%, and 900% ratios were interfaced with the metasurfaces. Metasurface resonances coinciding with the intrinsic nanofiber resonances─confirmed by Stokes polarimetry─produced the strongest colorimetric enhancement, resulting from alignment-specific nanofiber reflectivity. The enhancement degree corresponded with molecular and bulk alignments for each draw ratio, as measured through differential scanning calorimetry and scanning electron microscopy. Thus, Meta-PAD presents an all-optical, nondestructive, quantitative measurement of nanofiber alignment.

Metasurfaces have pioneered significant improvements in sensing technology by tailoring strong optical responses to weak signals. When designed with anisotropic subwavelength geometries, metasurfaces can tune responses to varying polarization states of light. Leveraging this to quantify structural alignment in fibrous materials unveils an alternative to destructive characterization methods. This work introduces metasurface-enhanced polarized light microscopy (Meta-PoL), which employs polarization-tunable, guided-mode-resonant colorimetric metasurfaces to characterize molecular and bulk alignment of poly(ε-caprolactone) (PCL) nanofibers in a far-field configuration. PCL nanofibers drawn at 0%, 400%, and 900% ratios were interfaced with the studied metasurfaces. Metasurface resonances coinciding with the intrinsic drawn nanofiber resonances - confirmed by Stokes Polarimetry - produced the strongest colorimetric enhancement, resultant from alignment-specific nanofiber reflectivity. The enhancement degree corresponded with molecular and bulk alignments for each draw ratio, as measured through differential scanning calorimetry and scanning electron microscopy, respectively. Thus, Meta-PoL presents an all-optical, non-destructive, and quantitative measurement of nanofiber alignment.

Abstract Structural coloration, a color‐generation mechanism often found in nature, arises from light–matter interactions such as diffraction, interference, and scattering, with micro‐ and nanostructured elements. Herein, we systematically study anisotropic, 3D‐architected grating structures with polarization‐tunable optical properties, inspired by the vivid blue of Morpho butterfly wings. Using two‐photon lithography, we fabricate multilayered gratings, varying parameters such as height (through scanning speed and laser power), periodicity, and number of layers. In transmission, significant color transitions from blue to brown were identified when varying structural parameters and incident light polarization conditions (azimuthal angle and ellipticity). Based on thin film diffraction efficiency theory in the Raman–Nath regime, optical characterization results are analytically explained, evaluating the impact of each parameter variation. Overall, these findings contribute to technological implementations of polarization‐sensitive, 3D‐architected gratings for structural color applications.

Biological Tissue Microstructures The Morpho butterfly wing is a natural photonic crystal that interacts selectively with polarized light. Lisa V. Poulikakos and co-workers interface the Morpho wing with breast cancer tissue sections and illuminate the system with polarized light for quantitative, contact- and stain-free assessment of tissue microstructures. This imaging approach enables improved understanding of the role of tissue microstructure in the origin and progression of disease. More details can be found in article number 2407728.

All-dielectric metasurfaces can produce structural colors, but the most advantageous design criteria are still being investigated. This work numerically studies how the two-dimensional shape of nanoparticles affects the colorimetric response under circularly polarized light (CPL) to develop a sensor distinguishing CPL orientations. Using lossless dielectric materials (silicon nitride on silicon dioxide), we achieve far-field dichroism by modifying oblong nanoparticles into L-shaped structures through corner cuts. This design suppresses one resonator mode under CPL illumination, leading to differential colorimetric responses. We link these responses to a decoupling effect in the near-field net electric flux. Our findings provide design guidelines for all-dielectric, lossless colorimetric sensors of chiral light.

Plasmonic nanoparticles exhibit strong optical scattering and absorption due to enhanced coupling to incident electromagnetic waves, while their efficient photothermal heating enables effective conversion of electromagnetic to mechanical energy. In this work, we put forward a theoretical framework for acoustoplasmonics, where plasmonic nanoparticles control the acoustic wavefront with light. We model the coupled optical, thermoelastic and acoustic mechanisms for gold nanospheres (AuNSs) and nanoellipsoids (AuNEs), and find that each physical mechanism entails a distinct toolbox of parameters, which can be tailored for effective acoustoplasmonic design. Simple analytical studies are performed for AuNSs, both validating numerical models and enabling quasi-analytical wavefront shaping under long laser pulse durations. AuNEs introduce optical anisotropy, and we numerically demonstrate that the polarization-dependent optical absorption in AuNEs can lead to selective photoexcitation and subsequently polarization-tunable acoustic wave generation. Moreover, we investigate the varying acoustoplasmonic frequency regimes, where optical resonance arises due to electromagnetic frequency, while acoustic resonance relates to laser pulse duration. We demonstrate proof-of-concept acoustoplasmonic metasurface designs using these mechanisms for tunable acoustic wavefront shaping in the form of lensing and beam steering. We suggest that future acoustoplasmonic systems, optimized using the physical mechanisms discussed here, will find use in a variety of applications, including miniaturized ultrasonic imaging and high-frequency signal processing.

Changes in the density and organization of fibrous biological tissues often accompany the progression of serious diseases ranging from fibrosis to neurodegenerative diseases, heart disease and cancer. However, challenges in cost, complexity, or precision faced by existing imaging methodologies pose barriers to elucidating the role of tissue microstructure in disease. Here, we leverage the intrinsic optical anisotropy of the Morpho butterfly wing and introduce Morpho-Enhanced Polarized Light Microscopy (MorE-PoL), a stain- and contact-free imaging platform which enhances and quantifies the birefringent material properties of fibrous biological tissues. We develop a mathematical model, based on Jones calculus, which quantifies fibrous tissue density and organization. As a representative example, we analyze collagen-dense and collagen-sparse human breast cancer tissue sections and leverage our technique to assess the microstructural properties of distinct regions of interest. We compare our results with conventional Hematoxylin and Eosin (H&E) staining procedures and second harmonic generation (SHG) microscopy for fibrillar collagen detection. Our findings demonstrate that our MorE-PoL technique provides a robust, quantitative, and accessible route toward analyzing biological tissue microstructures, with great potential for application to a broad range of biological materials.

Supplement Document 1

Supplement Document 1

Structural coloration, a color-generation mechanism often found in nature, arises from light-matter interactions such as diffraction, interference and scattering, with micro- and nanostructured elements. Herein, we systematically study anisotropic, 3D-architected grating structures with polarization-tunable optical properties, inspired by the vivid blue of Morpho butterfly wings. Using two-photon lithography, we fabricate multilayered gratings, varying parameters such as height (through scanning speed and laser power), periodicity, and number of layers. In transmission, significant color transitions from blue to brown were identified when varying structural parameters and incident light polarization conditions (azimuthal angle and ellipticity). Based on thin film diffraction efficiency theory in the Raman-Nath regime, optical characterization results are analytically explained, evaluating the impact of each parameter variation. Overall, these findings contribute to technological implementations of polarization-sensitive, 3D-architected gratings for structural color applications.

All-dielectric metasurfaces can produce structural colors, but the most advantageous design criteria are still being investigated. This work numerically studies how the two-dimensional shape of nanoparticles affects the colorimetric response under circularly polarized light (CPL) to develop a sensor distinguishing CPL orientations. Using lossless dielectric materials (silicon nitride on silicon dioxide), we achieve far-field dichroism by modifying oblong nanoparticles into L-shaped structures through corner cuts. This design suppresses one electric dipole under CPL illumination, leading to differential colorimetric responses. We link these responses to a decoupling effect in the near-field net electric flux. Our findings provide design guidelines for all-dielectric, lossless colorimetric sensors of chiral light.

We leverage the Morpho and Papilio Blumei butterfly wings and the Chalcothea Smaragdina beetle shell, as a novel imaging platform to elucidate the fibrous properties of biological tissue. Unstained and fixed murine breast cancer tissue sections are studied with high and low collagen content. By interfacing histological tissue sections with the studied nature-derived structural color system, we achieve selective structural coloration of the tissue based on its fibrous properties in a contact-free and label-free manner. Using Jones calculus and color theory, we define key figures of merit which quantify the anisotropic optical properties of the fibrous tissue for the tissue-structural color system and for the tissue on its own. The enhancement of the tissue optical anisotropy with the nature-derived metasurfaces will then be assessed, showcasing the potential of this technique in various diagnostic applications.

The polarization-sensitivity of an optical array - a periodic assembly of subwavelength resonators - has been hypothesized to be correlated to the degree of asymmetry of its individual resonators. However, the lack of a global quantifying measure of asymmetry makes the purposeful design of asymmetric structures intractable. This work takes a bottom-up approach to investigate how the controlled violation of two-dimensional symmetry in regular polygon-shaped nanoscale resonators affects the polarization sensitivity of lattice resonant silicon nitride nano-optical arrays. By focusing on visible light, these arrays serve as color sensors for diverse polarized light domains. While rectangle-shaped resonators lack chirality for sensing varying chiral light orientations, removing corners enables the selective enhancement of near-field electric and magnetic moments in response to clockwise- and counterclockwise-orientations of circularly polarized light. This selective enhancement of near-field electric and magnetic moments leads to unique far-field spectra and enables the development of a chiral light orientation color sensor.

Metasurfaces are composed of sub-wavelength periodically arranged resonant structures that can manipulate wave-matter interactions in manners not observed in nature. All-optical and all-acoustic metasurfaces have separately demonstrated versatile capabilities such as lensing, beam steering or wavefront control. Here, we study a new class of acoustoplasmonic metasurfaces. By combining the physics of light and sound in previously unexplored ways, this platform enables entirely new avenues to harness the power of wave-matter interactions. This work paves the way toward versatile societal imaging applications ranging from environmental science to biomedical devices or industrial imaging.

Iridescent structural color is abundant in nature, arising in the saturated blues of the Morpho butterfly wing or the greens of jeweled beetle shells. At the micrometer scale and smaller, these naturally occurring, three-dimensionally (3D)-architected photonic crystals are composed of ordered, geometrically anisotropic features which exhibit distinct interactions with light at varying angles of incidence or polarization state. Due to their 3D hierarchical architecture, these nature-derived systems are unique sources of polarization-sensitive structural color with high color purity and brightness. Here, we explore the exemplary polarization-sensitive properties of nature-derived photonic crystals and identify their key photonic and optically anisotropic features. We then leverage this knowledge to develop a new class of nature-inspired, 3D-architected colorimetric metasurfaces to enhance polarization-sensitive structural color response beyond what is observed in nature.

Optical and acoustic metasurfaces have been extensively studied for wavefront shaping, including lensing, beam steering, and holography. This work aims to explore a new field of acoustoplasmonic metasurfaces that utilize the photoacoustic effect in gold nanoparticles to generate high-frequency acoustic waves via optical excitation. We leverage the extreme polarization-dependence of absorption efficiency in nanoellipsoids to introduce acoustic wavefront tunability, which opens the door to applications in super-resolution acoustic imaging.

Recent research has shown that the arrangement and density of extracellular fibers within the tumor microenvironment can signify breast cancer stage. However, most biological fibers possess inherently weak birefringence. This means visualizing these structures requires expensive and complex nonlinear optics or stains that necessitate laborious preparation and risk false diagnosis due to potential artifacts. Access to both options can be especially challenging in underserved settings, where marginalized groups are more susceptible to aggressive variants of breast cancer. We leverage the polarization-sensitive structural color in Morpho butterfly wings for stain-free imaging of extracellular fibers in breast cancer tissue biopsies. We quantitatively assessed the anisotropic colorimetric response of histological tissue sections interfaced with these nanophotonic materials. The promising diagnostic properties of this stain-free imaging platform introduces a new method of diagnostic imaging for rapid, precise, and low-cost tissue diagnostics.

Structured illumination microscopy (SIM) achieves superresolution in fluorescence imaging through patterned illumination and computational image reconstruction, yet current methods require bulky, costly modulation optics and high-precision optical alignment, thus hindering the widespread implementation of SIM. To address this challenge, this work demonstrates how nano-optical metasurfaces, rationally designed to tailor the far-field optical wavefront at sub-wavelength dimensions, hold great potential as ultrathin, single-surface, all-optical wavefront modulators for SIM. We computationally demonstrate this principle with a multipolar-resonant metasurface composed of silicon nanostructures that generate versatile optical wavefronts in the far field upon variation of the polarization or angle of incident light. Algorithmic optimization is performed to identify the seven most suitable illumination patterns for SIM generated by the metasurface based on three key criteria. We quantitatively demonstrate that multipolar-resonant metasurface SIM (mrm-SIM) achieves resolution gain that is comparable to conventional methods by applying the seven optimal metasurface-generated wavefronts to simulated fluorescent objects and reconstructing the objects using proximal gradient descent. Notably, we show that mrm-SIM achieves these resolution gains with a far-field illumination pattern that circumvents complex equipment and alignment requirements of comparable methodologies. The work presented here paves the way for a metasurface-enabled experimental simplification of structured illumination microscopy.

An additional deposition step was added to a multi-step electron beam lithographic fabrication process to unlock the height dimension as an accessible parameter for resonators comprising unit cells of quasi-bound states in the continuum metasurfaces, which is essential for the geometric design of intrinsically chiral structures.

Mie resonators as lattice resonant metasurfaces have the capability to produce structural color. However, design criteria for these metasurfaces are still being investigated. In this work, we numerically examined how the two-dimensional nanostructure shape in a lattice array affects the colorimetric response of the metasurface under linearly polarized light excitation. First, it was realized through near-field examinations that nodes of high-order resonances are localized to the corners of the rectangle-shaped nanostructures, where fundamental resonance nodes cannot be found. Second, removing the corners in rectangle-shaped nanostructures to create t-shaped nanostructure arrays displayed a dampening effect on the high-order resonance. Finally, analytical calculations of the color saturation showed increases upon moving from rectangle-shaped to t-shaped nanostructure arrays when a high-order resonance was dampened. From these results, we present a design guideline for lattice resonant metasurfaces: Removing portions of the nanostructure that support only high-order resonances dampens these modes while maintaining support for fundamental resonances. These results present a first-principles criterion for engineering nanoparticles in lattice resonant metasurfaces, offering a new toolbox addition for polarized light-sensing and colorimetric applications.

Iridescent structural color is abundant in nature, arising in the saturated blues of the Morpho butterfly wing or the greens of jewelled beetle shells. At the micrometer scale and smaller, these naturally occurring, three-dimensionally (3D)-architected photonic crystals are composed of ordered, geometrically anisotropic features which exhibit distinct interactions with polarized light. Here, we design artificial 3D-architected colorimetric metasurfaces. We use two-photon lithography to fabricate multilayer grating structures which surpass the polarization-sensitive colorimetric response attainable in nature. Bringing additive manufacturing to the regime of visible light-matter interactions, our metasurfaces hold promise for versatile imaging, display and sensing technologies.

The polarization sensitivity of a nano-optical array is hypothesized to correlate with the degree of asymmetry of its individual nanostructures. This work takes a top-down approach to investigate how controlled violations of two-dimensional symmetry in regular polygon-shaped nanostructures affect the polarization sensitivity of lattice resonant, dielectric nano-arrays. Such nanoarrays dampen higher-order Mie resonances while maintaining the fundamental Mie resonance. Isolating a fundamental Mie resonance in the visible region of the electromagnetic spectrum permits the mapping of a spectrum to a high-purity color. Through this, it becomes possible to build a colorimetric sensor of domains of rotations of linearly polarized light.

Imaging techniques with subdiffraction-limited spatial resolutions are highly desired for a deeper understanding of subcellular systems. Optical imaging enables high resolution under 200 nm while the visible light penetration depth is limited to merely 2 mm. Ultrasound images achieve two orders of magnitude lower resolutions but can penetrate two orders of magnitude deeper into a medium than optical images. This work combines the strengths of optical and acoustic imaging techniques through AuNP-based metasurfaces utilizing the photoacoustic effect that gold exhibits. Our novel imaging technique can simultaneously achieve high resolution and deep penetration depths without any destruction of media.

Fibrotic diseases account for one-third of deaths worldwide, making it essential to investigate the accompanying tissue microstructural changes that are critical to disease progression. This research focuses on the fibrotic extracellular matrices present in histological tissue sections, which can characterize disease progression. We demonstrate how bioinspired structural color can be utilized as a label-free technology to determine disease progression on a single nanostructured surface. This nanophotonic imaging platform characterizes the organization of fibrous biological tissues with distinct stain-free color responses. The colorimetric response of histological tissue sections interfaced with these nanostructured slides was quantitatively assessed.