<p>This work presents the numerical design and computational analysis of a biosensing platform that utilizes a two-dimensional photonic crystal structure with a silicon rods-in-air configuration, intended for the precise detection and measurement of urinary biomarkers such as glucose, urea, and albumin. The design incorporates a linear waveguide coupled to a central hexagonal ring resonator, in which changes in the refractive index of the analyte induce measurable resonant wavelength shifts that form the basis of the sensing mechanism. The photonic band structure of the sensor is computed using the plane-wave expansion method, whiles its transmission spectrum and resonant characteristics are evaluated through a finite-difference time-domain approach. Through parametric optimization of the sensing rod radius, the design achieves a high sensitivity of 900 nm/RIU and a high quality factor of 1.4267<InlineEquation ID="IEq1"> <EquationSource Format="TEX">$\times$</EquationSource> <EquationSource Format="MATHML"><math> <mo>×</mo> </math></EquationSource> </InlineEquation>10<InlineEquation ID="IEq2"> <EquationSource Format="TEX">$^\textrm{6}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mtext>6</mtext> </mmultiscripts> </math></EquationSource> </InlineEquation>, along with a low detection limit of 1.276<InlineEquation ID="IEq3"> <EquationSource Format="TEX">$\times$</EquationSource> <EquationSource Format="MATHML"><math> <mo>×</mo> </math></EquationSource> </InlineEquation>10<InlineEquation ID="IEq4"> <EquationSource Format="TEX">$^{-7}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mrow> <mo>-</mo> <mn>7</mn> </mrow> </mmultiscripts> </math></EquationSource> </InlineEquation> RIU and an impressive figure of merit of 7.8372<InlineEquation ID="IEq5"> <EquationSource Format="TEX">$\times$</EquationSource> <EquationSource Format="MATHML"><math> <mo>×</mo> </math></EquationSource> </InlineEquation>10<InlineEquation ID="IEq6"> <EquationSource Format="TEX">$^\textrm{5}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mtext>5</mtext> </mmultiscripts> </math></EquationSource> </InlineEquation> RIU<InlineEquation ID="IEq7"> <EquationSource Format="TEX">$^{-1}$</EquationSource> <EquationSource Format="MATHML"><math> <mmultiscripts> <mrow /> <mrow /> <mrow> <mo>-</mo> <mn>1</mn> </mrow> </mmultiscripts> </math></EquationSource> </InlineEquation>. The sensor demonstrates excellent linearity, with correlation coefficients of 0.99995 for glucose and 0.99957 for urea. Furthermore, the impact of fabrication-induced disorders on performance is analyzed to assess robustness. A three-dimensional simulation validates the design’s feasibility, and a feasible fabrication process is outlined for future experimental realization. With a compact footprint of 130.235 <InlineEquation ID="IEq8"> <EquationSource Format="TEX">$\upmu \text {m}^2$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi mathvariant="normal">μ</mi> <msup> <mtext>m</mtext> <mn>2</mn> </msup> </mrow> </math></EquationSource> </InlineEquation>, the proposed design is well suited for photonic integrated circuit applications.</p>

Numerical design and performance analysis of a compact on-chip photonic crystal biosensor for urine biomarker detection

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发表日期：

2026年1月21日

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Shivesh Kumar,
Haraprasad Mondal,
Mrinal Sen

摘要

This work presents the numerical design and computational analysis of a biosensing platform that utilizes a two-dimensional photonic crystal structure with a silicon rods-in-air configuration, intended for the precise detection and measurement of urinary biomarkers such as glucose, urea, and albumin. The design incorporates a linear waveguide coupled to a central hexagonal ring resonator, in which changes in the refractive index of the analyte induce measurable resonant wavelength shifts that form the basis of the sensing mechanism. The photonic band structure of the sensor is computed using the plane-wave expansion method, whiles its transmission spectrum and resonant characteristics are evaluated through a finite-difference time-domain approach. Through parametric optimization of the sensing rod radius, the design achieves a high sensitivity of 900 nm/RIU and a high quality factor of 1.4267 $\times$ $\times$ 10 $^\textrm{6}$ $^{6}$ , along with a low detection limit of 1.276 $\times$ $\times$ 10 $^{-7}$ $^{- 7}$ RIU and an impressive figure of merit of 7.8372 $\times$ $\times$ 10 $^\textrm{5}$ $^{5}$ RIU $^{-1}$ $^{- 1}$ . The sensor demonstrates excellent linearity, with correlation coefficients of 0.99995 for glucose and 0.99957 for urea. Furthermore, the impact of fabrication-induced disorders on performance is analyzed to assess robustness. A three-dimensional simulation validates the design’s feasibility, and a feasible fabrication process is outlined for future experimental realization. With a compact footprint of 130.235 $\upmu \text {m}^2$ $μ m^{2}$ , the proposed design is well suited for photonic integrated circuit applications.