arXiv subjects

Emiliano R. Martins

Publications and source records attributed to Emiliano R. Martins.

4 recordsLinked to original sources

arXiv2026

High resolution meta-stereomicroscope based on birefringent meta-optics

Achieving both high lateral and high depth resolution is a longstanding goal in stereomicroscopy. Although meta-optics have revolutionized lens design by alleviating the physical constraints of conventional optical architectures, existing metalens-assisted stereomicroscopes still suffer from field of view (FOV) mismatch between meta-optical and conventional optical components in stereomicroscopes, thereby limiting their imaging performance. Here, we show that this mismatch can be fundamentally eliminated through a fully meta-optical architecture. The integrated system enables flexible control of numerical aperture and magnification with larger depth of field (DOF) and FOV than those of the metalens-assisted stereomicroscopes. Experimentally, we achieve an integrated meta-stereomicroscope with a lateral resolution of 435 nm, surpassing the performance of previously reported stereomicroscopes. Empowered by a stereo neural network, the system enables straightforward reconstruction of high-resolution three-dimensional surface morphology with a depth resolution of 1026 nm, demonstrating the capability to simultaneously achieve high lateral and depth resolution imaging. This integrated architecture operates in both transmission and reflection modes for biomedical imaging and industrial inspection, highlighting its broad applicability for real-time observation across biomedical and industrial scenarios.

physics.optics↗

arXiv2025

Ultrasensitive Anti-Stokes Luminescence Thermometry in Transition Metal Dichalcogenide Monolayers

Accurate temperature mapping at the nanoscale is a critical challenge in modern science and technology, as conventional methods fail at these dimensions. To address this challenge, we demonstrate a highly sensitive nanothermometer using anti-Stokes photoluminescence, also known as photoluminescence upconversion (UPL), in monolayer tungsten disulfide ($\mathrm{WS_2}$). Leveraging the direct band gap and strong exciton-phonon coupling in the two-dimensional monolayers, we achieve an exceptional relative sensitivity above $4\%\,\mathrm{K}^{-1}$ across the 300 K to 425 K range, ranking it among the best-performing materials reported. A strong resonantly enhanced UPL is observed, confirming the central role of optical phonons in the upconversion mechanism. Furthermore, we introduce a new analytical model to quantitatively describe the UPL process, taking into account the interplay of phonon populations, bandgap narrowing, and substrate effects, which predicts resonant temperatures and provides a framework with broad applicability to any material exhibiting an anti-Stokes photoluminescence response. To demonstrate its use as a high-resolution optical thermometer, we map a $20\,^{\circ}\mathrm{C}$ thermal gradient across a $20\,μ\mathrm{m}$ long monolayer with a spatial resolution of $1\,μ\mathrm{m}$. With its high sensitivity, strong signal, and excellent reproducibility, our work establishes monolayer transition metal dichalcogenide as a leading platform for non-invasive thermal sensing in advanced microelectronic and biological systems.

cond-mat.mtrl-sci↗

arXiv2025

Ultrasensitive Alzheimer's Disease Biomarker Detection with Nanopillar Photonic Crystal Biosensors

The recent development of drugs able to mitigate neurodegenerative diseases has created an urgent need for novel diagnostics. Although biomarker detection directly in patients' blood is now possible, low-cost point-of-care tests remain a challenge, because relevant biomarkers, especially amyloid-β(A$β$) peptides, are small, they occur at very low concentrations, and detecting a single marker is insufficient. Here, we introduce an optical biosensor based on a nanopillar structure that employs a gold nanoparticle amplification strategy. The sensor is able to detect 20 pg/ml of A$β$42 and A$β$40 in undiluted serum, which is the clinically required level. We also show the detection of the A$β$42 and A$β$40 peptides in the same channel, which is highly relevant for assessing disease progress and opens a route towards multiplexing. Alongside their simplicity and portability, these nanotechnology innovations make a major contribution to the ability to detect and monitor the progression of neurodegenerative diseases such as Alzheimer's.

physics.optics↗

arXiv2022

Correction of aberrations via polarization in single layer metalenses

The correction of multiple aberrations in an optical system requires different optical elements, which increases its cost and complexity. Metasurfaces hold great promise to providing new functionality for miniaturized and low-cost optical systems. A key advantage over their bulk counterparts is the metasurface's ability to respond to the polarization of light, which adds a new degree of freedom to the optical design. Here, we show that polarization control enables a form-birefringent metalens to correct for both spherical and off-axis aberrations using a single element only, which is not possible with bulk optics. The metalens encodes two phase profiles onto the same surface, thus allowing switching from high resolution to wide field of view operation. Such ability to obtain both high resolution and wide field of view in a single layer is an important step towards integration of miniaturized optical systems, which may find many applications, e.g., in microscopy and endoscopy.

physics.optics↗