arXiv subjects

Majid Aalizadeh

Publications and source records attributed to Majid Aalizadeh.

7 recordsLinked to original sources

arXiv2026

Multi-Wavelength Machine Learning for High-Precision Colorimetric Sensing

Conventional colorimetric sensing methods typically rely on signal intensity at a single wavelength, often selected heuristically based on peak visual modulation. This approach overlooks the structured information embedded in full-spectrum transmission profiles, particularly in intensity-based systems where linear models may be highly effective. In this study, we experimentally demonstrate that applying a forward feature selection strategy to normalized transmission spectra, combined with linear regression and ten-fold cross-validation, yields significant improvements in predictive accuracy. Using food dye dilutions as a model system, the mean squared error was reduced from over 22,000 with a single wavelength to 3.87 using twelve selected features, corresponding to a more than 5,700-fold enhancement. These results validate that full-spectrum modeling enables precise concentration prediction without requiring changes to the sensing hardware. The approach is broadly applicable to colorimetric assays used in medical diagnostics, environmental monitoring, and industrial analysis, offering a scalable pathway to improve sensitivity and reliability in existing platforms.

physics.med-ph↗

arXiv2025

Accuracy Enhancement in Refractive Index Sensing via Full-Spectrum Machine Learning Modeling

We present a full-spectrum machine learning framework for refractive index sensing using simulated absorption spectra from meta-grating structures composed of titanium or silicon nanorods under TE and TM polarizations. Linear regression was applied to 80 principal components extracted from each spectrum, and model performance was assessed using five-fold cross-validation, simulating real-world biosensing scenarios where unknown patient samples are predicted based on standard calibration data. Titanium-based structures, dominated by broadband intensity changes, yielded the lowest mean squared errors and the highest accuracy improvements: up to a 6065-fold reduction compared to the best single-feature model. In contrast, silicon-based structures, governed by narrow resonances, showed more modest gains due to spectral nonlinearity that limits the effectiveness of global linear models. We also show that even the best single-wavelength predictor is identified through data-driven analysis, not visual selection, highlighting the value of automated feature preselection. These findings demonstrate that spectral shape plays a key role in modeling performance and that full-spectrum linear approaches are especially effective for intensity-modulated index sensors.

physics.optics↗

arXiv2025

Development of a Miniaturized, Automated, and Cost-Effective Device for Enzyme-Linked Immunosorbent Assay

In this work, a miniaturized, automated, and cost-effective ELISA device is designed and implemented, without the utilization of conventional techniques such as pipetting or microfluidic valve technologies. The device has dimensions of 24 cm x 19 cm x 14 cm and weighs <3 Kg. The total hardware cost of the device is estimated to be approximately $1,200, which can be further reduced through optimization during scale-up production. 3D printed disposable parts, including the reagent reservoir disk and the microfluidic connector, have also been developed. IL-6 is used as a model system to demonstrate how the device provides an ELISA measurement. The cost per test is estimated to be less than ten dollars. The compactness, automated operation, along with the cost-effectiveness of this ELISA device, makes it suitable for point-of-care applications in resource-limited regions.

physics.med-ph↗

arXiv2025

Machine Learning-Enabled Multidimensional Data Utilization Through Multi-Resonance Architecture: A Pathway to Enhanced Accuracy in Biosensing

A novel framework is proposed that combines multi-resonance biosensors with machine learning (ML) to significantly enhance the accuracy of parameter prediction in biosensing. Unlike traditional single-resonance systems, which are limited to one-dimensional datasets, this approach leverages multi-dimensional data generated by a custom-designed nanostructure, a periodic array of silicon nanorods with a triangular cross-section over an aluminum reflector. High bulk sensitivity values are achieved for this multi-resonant structure, with certain resonant peaks reaching up to 1706 nm/RIU. The field analysis reveals Mie resonances as the physical reason behind the peaks. The predictive power of multiple resonant peaks from transverse magnetic (TM) and transverse electric (TE) polarizations is evaluated using Ridge Regression modeling. Systematic analysis reveals that incorporating multiple resonances yields up to three orders of magnitude improvement in refractive index detection precision compared to single-peak analyses. This precision enhancement is achieved without modifications to the biosensor hardware, highlighting the potential of data-centric strategies in biosensing. The findings establish a new paradigm in biosensing, demonstrating that the synergy between multi-resonance data acquisition and ML-based analysis can significantly enhance detection accuracy. This study provides a scalable pathway for advancing high-precision biosensing technologies.

q-bio.QM↗

arXiv2019

Electromagnetic Field Tapering in the High-Roughness Substrates Coated by a Thin Film of Manganese: A Lithography-Free Approach to Ultra-Broadband, Wide-Angle, UV to FIR Perfect Absorption

Metallic layers are known to be used for the suppression of wave transmission when their thickness is sufficiently higher than the skin depth of metal. If in addition to blocking the transmission, metallic layers have the feature of blocking the reflection, too, they would make perfect absorbers. In this work, we propose an experimental approach of using a single thin layer of Manganese (Mn) as both the transmission suppresser and the reflection suppresser. This approach leads to obtaining lithography-free ultra-broadband perfect absorption in an ultra-wide spectrum ranging from Ultraviolet (UV) to Far Infrared (FIR). The measured average absorption is approximately 99%. Such a promising result can be achieved by only coating a single Mn layer on high-roughness substrates that include random nano-pyramids on it. In other words, we do not need a stack of different materials and combinations of geometrical features. The high roughness is realized on a commercial Silicon wafer substrate by inductively coupled plasma (ICP) etching. The key to this ultra-wideband absorption is electromagnetic field tapering which exists due to the graded-index feature of the structure (known as moth-eye effect), along with the ideal optical properties of Mn which makes it an excellent metal for broadband absorption applications. A full experimental characterization of the fabricated samples is presented along with the physical analysis of the phenomena. The findings of this paper can be used for the realization of lithography-free, cost-effective and high-throughput mass production of broadband absorbers.

physics.optics↗

arXiv2018

Lithography-Free, Manganese-Based Ultra-Broadband Absorption Through Annealing-Based Deformation of Thin Layers into metal-air composites

Fabrication, characterization, and analysis of an ultra-broadband lithography-free absorber is presented. An over 94% average absorption is experimentally achieved in the wavelength range of 450-1400 nm. This ultra-broadband absorption is obtained by a simple annealed tri-layer metal-insulator-metal (MIM) configuration. The metal used in the structure is Manganese (Mn), which also makes the structure cost-effective. It is shown that the structure retains its high absorption for TM polarization, up to 70 degrees, and, for TE polarization, up to 50 degrees. Moreover, the physical mechanism behind this broadband absorption is explained. Being both lithography-free and cost-effective, the structure is a perfect candidate for large-area and mass production purposes.

physics.optics↗

arXiv2018

A Route to Unusually Broadband Absorption Spanning from Visible to Mid-Infrared

In this paper, a route to ultra-broadband absorption is suggested and demonstrated by a feasible design. The high absorption regime (absorption above 90%) for the suggested structure ranges from visible to mid-infrared (MIR), i.e. for the wavelength from 478 to 3,278 nm that yields an ultra-wide bandwidth of 2,800 nm. The structure consists of a top-layer-patterned metal-insulator-metal (MIM) configuration, into the insulator layer of which, an ultra-thin 5 nm layer of Manganese (Mn) is embedded. The MIM configuration represents a Ti-Al2O3-Ti tri-layer. It is shown that, without the ultra-thin layer of Mn, the absorption bandwidth is reduced to 274 nm. Therefore, adding only a 5 nm layer of Mn leads to a more than tenfold increase in the width of the absorption band. It is explained in detail that the physical mechanism contributing to this ultra-broadband result is a combination of plasmonic and non-plasmonic resonance modes, along with the appropriate optical properties of Mn. This structure has the relative bandwidth (RBW) of 149%, while only one step of lithography is required for its fabrication, so it is relatively simple to fabricate. This makes it rather promising for practical applications.

physics.optics↗