Metamaterial absorber and sensing mechanism

Absorber with its sensing mechanism

1. Electromagnetic spectrum Fig.1. Electromagnetic Spectrum [1] Terahertz spectrum Wavelengths range from 10 micrometre to 1 millimetre and frequency range from 0.1 THz to 10 THz. THz radiation is non-ionizing due to its small photon energy (4.1 to 14 meV ) and is considered safe for imaging purposes.  It can penetrate up to several millimetre into thin layers of metallic substance but not in biological tissues. Applications of Terahertz Technology  Medical imaging for detecting cancer cells Security screening for detecting concealed weapons Studying chemical reactions in chemistry Data transfer in wireless communications Introduction

2. Metamaterials are artificial materials which exhibit unique properties which do not occur in nature. A Metasurface is a planar periodic array of identical, electrically thin unit cells whose lateral extent is a small fraction of the free-space wavelength λ . The unit cell of a Metasurface is called meta-atom . Exhibiting effective electric ( ), and magnetic ( μ ) response not found in nature. Distance between unit cells lies in the sub-wavelength region.   A << λ Metamaterials A λ Photonic Crystal   A >> λ Reflection, refraction, shadow A/ λ Fig.2. Metamaterial [2] Introduction: Metamaterial

3. μ ε E H K S Dielectric ε > 0, μ > 0 Propagating Waves E K Magnetic plasma ε > 0, μ < 0 Evanescent Waves E K Electric plasma (Metals, Doped semiconductor) ε < 0, μ > 0 Evanescent Waves E H K S Negative index (not found in nature, but physically realizable) ε < 0, μ < 0 Propagating Waves Fig.3. Metamaterial classification based on ε and μ Introduction: Metamaterial Contd..

4. Right-handed rule Left-handed rule Fig.4. Metamaterial classification based on hand rule Introduction: Metamaterial Contd..

5. If a medium has a negative permittivity and negative permeability, it indicates a negative refractive index. When the refractive index is negative, the speed of the waves is negative and travels in the backward direction w.r.t. source. Left-handed metamaterial, wave propagates in the opposite direction to the energy flows. Introduction: Physical interpretation of negative refractive index

6. Absorbing power,     Input Impedance, (as )   , Condition for metamaterial absorption     Introduction: Metamaterial Absorber

7. Integrated receptor- transducer device, which can convert a biological response into an electrical signal.  Metamaterial absorbers have the tendency to sense in the terahertz domain. Biosensor applications- health care and disease diagnosis, environmental monitoring, water and food quality monitoring, and drug delivery. Analyte- Sample whose sensing needs to be done. Introduction: Biosensors

8. Biosensors: Sensing parameters Fig.8. Illustration of FWHM

9. Working principles of THz Biosensor The working principle of a terahertz biosensor is mainly based on the refractive index sensing and thin film sensing of the analytes on the sensor’s surface. With change in the refractive index/thickness of analyte, there is a shift in frequency in the absortion or transmittance curve. Impedance of free space matches with the impedance of the biosensor. Fig.9 Sensing mechanism [4]

10. Literature Survey S.No . Authors Title of the Paper (Journal) Structure Materials Results Outcomes and observations 1. M.S. Khan, G. Varshney Altering the multimodal resonance in ultrathin Silicon ring for tunable THz Biosensing [5]. Gold, , Silicon, Graphene Resonant frequency-4.75 and 5.12 THz Thickness- 3.65 μ m Polarization Insensitive. 2. P. Upender , A. Kumar Ultrathin, Ultra Narrow Band DMMA for Biosensing applications [6]. Gold, , Silicon, Graphene Resonant frequency- 6.16 and 6.84 THz Thickness- 4 μ m Polarization insensitive. S.No . Authors Title of the Paper (Journal) Structure Materials Results Outcomes and observations 1. M.S. Khan, G. Varshney Altering the multimodal resonance in ultrathin Silicon ring for tunable THz Biosensing [5]. Resonant frequency-4.75 and 5.12 THz Thickness- 3.65 μ m Polarization Insensitive. 2. P. Upender , A. Kumar Ultrathin, Ultra Narrow Band DMMA for Biosensing applications [6]. Resonant frequency- 6.16 and 6.84 THz Thickness- 4 μ m Polarization insensitive.

11. Literature Survey S.No . Authors Title of the Paper (Journal) Structure Materials Results Outcomes and observations 3. Y. Chen, Y. Cheng, D. Meng , K. You, Y. Liu, Y. Wu, J. Liu Terahertz refractive index sensor based on tunable patterned graphene absorber [7]. Graphene, , Gold Resonant frequency- 3.94 and 8.28 THz Thickness- 3.17 μ m Polarization Insensitive. 4. P. Upender , A. Kumar THz Dielectric Metamaterial sensor with high Q for biosensing applications [8]. Gold, Silicon, Graphene Resonant frequency-4.06 THz Thickness- 3.45 μ m Polarization insensitive. S.No . Authors Title of the Paper (Journal) Structure Materials Results Outcomes and observations 3. Y. Chen, Y. Cheng, D. Meng , K. You, Y. Liu, Y. Wu, J. Liu Terahertz refractive index sensor based on tunable patterned graphene absorber [7]. Resonant frequency- 3.94 and 8.28 THz Thickness- 3.17 μ m Polarization Insensitive. 4. P. Upender , A. Kumar THz Dielectric Metamaterial sensor with high Q for biosensing applications [8]. Resonant frequency-4.06 THz Thickness- 3.45 μ m Polarization insensitive.

12. Literature Survey S.No . Authors Title of the Paper (Journal) Structure Materials Results Outcomes and observations 5. L. Ma, Y. Liu, Y. Zhu, W. Gu Sensing Performance of Triple-Band Terahertz Metamaterial Absorber Based on Snowflake-Shaped Resonators [9] (Photonics). Metal, dielectric, metal, analyte Resonant frequency- 0.55, 1.25, and 1.87 THz Thickness- 10.3 μ m Polarization Insensitive. 6. P. Zamzam , P. Rezaei , S. A. Khatami Quad-band polarization-insensitive metamaterial perfect absorber based on bilayer graphene metasurface [10] (Elsevier). Gold, , Graphene Resonant frequency- 2.7, 3.2, 3.99, 4.6 THz Thickness- 12.1 μ m Polarization insensitive. S.No . Authors Title of the Paper (Journal) Structure Materials Results Outcomes and observations 5. L. Ma, Y. Liu, Y. Zhu, W. Gu Sensing Performance of Triple-Band Terahertz Metamaterial Absorber Based on Snowflake-Shaped Resonators [9] (Photonics ). Metal, dielectric, metal, analyte Resonant frequency- 0.55, 1.25, and 1.87 THz Thickness- 10.3 μ m Polarization Insensitive. 6. P. Zamzam , P. Rezaei , S. A. Khatami Quad-band polarization-insensitive metamaterial perfect absorber based on bilayer graphene metasurface [10] (Elsevier ). Resonant frequency- 2.7, 3.2, 3.99, 4.6 THz Thickness- 12.1 μ m Polarization insensitive.

13. Literature Survey S.No . Authors Title of the Paper (Journal) Structure Materials Results Outcomes and observations 7. S. Khatami, P. Rezaei , P. Zamzam Quad band metal‑dielectric‑metal perfect absorber to selective sensing application [11] (Springer Nature). Gold, , Gold Resonant frequency- 1.36, 2.6, 3.68, 4.36 THz Thickness- 12.2 μ m Polarization Sensitive. 8. V. Maurya, S. Singhal Ultrathin Multi-band polarization-Independent Terahertz absorber as a biosensor [12]. (IEEE Sensors Journal) Analyte, Polyimide, Gold Resonant frequency- 2.8, 7.63, 14.42, 20.52, 23.54, 25.46 THz Thickness- μ m Polarization insensitive. S.No . Authors Title of the Paper (Journal) Structure Materials Results Outcomes and observations 7. S. Khatami, P. Rezaei , P. Zamzam Quad band metal‑dielectric‑metal perfect absorber to selective sensing application [11] (Springer Nature ). Resonant frequency- 1.36, 2.6, 3.68, 4.36 THz Thickness- 12.2 μ m Polarization Sensitive. 8. V. Maurya, S. Singhal Ultrathin Multi-band polarization-Independent Terahertz absorber as a biosensor [12]. (IEEE Sensors Journal ) Analyte, Polyimide, Gold Resonant frequency- 2.8, 7.63, 14.42, 20.52, 23.54, 25.46 THz Thickness- μ m Polarization insensitive.

14. Research Gaps Tunability of each band For sensing purpose, improving quality factor, and sensitivity Polarisation insensitive absorber Multiband absorber Metal free absorber

15. References [1] A. Salcedo and E. Martinez, "Analysis of the Electromagnetic Spectrum under the Extremely Low Frequency Band: Frequency Sub-Bands Classification," 2017 International Conference on Mechatronics, Electronics and Automotive Engineering (ICMEAE), Cuernavaca, Mexico, 2017, pp. 157-162, doi : 10.1109/ICMEAE.2017.15. [2] S. A. Tretyakov , S. Maslovski and P. A. Belov , "An analytical model of metamaterials based on loaded wire dipoles," in IEEE Transactions on Antennas and Propagation, vol. 51, no. 10, pp. 2652-2658, Oct. 2003, doi : 10.1109/TAP.2003.817557. [3] R. W. Ziolkowski , "Design, fabrication, and testing of double negative metamaterials," in IEEE Transactions on Antennas and Propagation, vol. 51, no. 7, pp. 1516-1529, July 2003, doi : 10.1109/TAP.2003.813622. [4] A. Mohanty , O. P. Acharya, B. Appasani , S. K. Mohapatra and M. S. Khan, "Design of a Novel Terahertz Metamaterial Absorber for Sensing Applications," in IEEE Sensors Journal, vol. 21, no. 20, pp. 22688-22694, 15 Oct.15, 2021, doi : 10.1109/JSEN.2021.3109158.

16. References [5] M. S. Khan, G. Varshney and P. Giri , "Altering the Multimodal Resonance in Ultrathin Silicon Ring for Tunable THz Biosensing ," in IEEE Transactions on NanoBioscience , vol. 20, no. 4, pp. 488-496, Oct. 2021, doi : 10.1109/TNB.2021.3105561. [6] P. Upender and A. Kumar, "Ultrathin, Ultra Narrow Band DMMA for Biosensing Applications," in IEEE Transactions on NanoBioscience , vol. 22, no. 3, pp. 529-537, July 2023, doi:10.1109/TNB.2022.321 07. [7] Yu- shan Chen, Yu- yao Cheng, Dan Meng , Ke-wei You, Yue Liu, Yong- chang Wu, Jing Liu, “Terahertz refractive index sensor based on tunable patterned graphene absorber”, Diamond and Related Materials, Volume 131, 2023, 109537, ISSN 0925-9635, https://doi.org/10.1016/j.diamond.2022.109537 . [8] P. Upender and A. Kumar, "THz Dielectric Metamaterial Sensor With High Q for Biosensing Applications," in IEEE Sensors Journal, vol. 23, no. 6, pp. 5737-5744, 15 March15, 2023, doi : 10.1109/JSEN.2023.3239669.

17. References [9] Ma L, Liu Y, Zhu Y, Gu W. Sensing Performance of Triple-Band Terahertz Metamaterial Absorber Based on Snowflake-Shaped Resonators.  Photonics . 2022; 9(10):777. https://doi.org/10.3390/photonics91 00777 . [10] Pouria Zamzam , Pejman Rezaei , Seyed Amin Khatami, “Quad-band polarization-insensitive metamaterial perfect absorber based on bilayer graphene metasurface ”, Physica E: Low-dimensional Systems and Nanostructures, Volume 128, 2021, 114621, ISSN 1386-9477, https://doi.org/10.1016/j.physe.2021.114621 . [11] Khatami, S.A., Rezaei , P. & Zamzam , P. Quad band metal-dielectric-metal perfect absorber to selective sensing application.  Opt Quant Electron   54 , 638 (2022). https://doi.org/10.1007/s11082-022-03948-6 . [12] V. Maurya and S. Singhal , "Ultrathin Multiband Polarization-Independent Terahertz Absorber as a Biosensor," in IEEE Sensors Journal, vol. 23, no. 21, pp. 25919-25926, 1 Nov.1, 2023, doi : 10.1109/JSEN.2023.3311018.

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