Paper presentation

1. Photonic Crystal Fiber based Surface Plasmon
Resonance Biosensor: Design and Investigation
Supervised by:
Dr. Md. Abir Hossain
Associate Professor
Dept. of ICT , MBSTU
3 March 2024 1
IT-16021 IT-16026
Department of Information and Communication Technology (ICT)
Mawlana Bhashani Science and Technology University
Santosh, Tangail-1902
Bangladesh
Presented by:
1. Md. Sajal Hossain (IT-16021)
2. Md. Afzalur Rahman Tanzin(IT-16026)

2. Contents
 Motivations
 Objectives
 Optical sensor and it’s applications
 Conventional fiber vs Photonic Crystal Fiber
 Surface Plasmon Resonance
 Design
 Methodology
 Numerical Analysis
 Result Analysis
 Comparison Table
 Conclusion
 References
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3. Motivations
 By studying these papers we realised that we have a lot of scope to improve in this field .
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Ref. [1] Ref. [2] Ref. [3]
 Complex structure
 Low sensitivity
 Complex structure
 Low sensitivity
 Low sensitivity

4. Objectives
 To gain higher sensitivity responses.
 To design a simple structure.
 To reduce the complexity of fabrication process.
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5. Plasmonic Sensor
 A plasmonic sensor is a kind of sensor that used to sense using the characteristics of surface plasmon
resonance(SPR).
 For high sensitivity and level-free sensing properties, this kind of optical sensor using SPR have
shown remarkable development with high level accuracy of sensing in recent past.
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6. Applications of Plasmonic Sensor
Optical sensor are commonly used in :
 Biological sample detection.
 Medical diagnostics.
 Environmental monitoring.
 Food quality control.
 Organic-chemical sensing. etc.
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7. Surface Plasmons Resonance (SPR)
 SPR is a physical process that can occur when plane-polarized light hits a
thin metal film under total internal reflection conditions [4]. Most
commonly used metal are Gold(Au), Silver(Ag), Copper(Cu) and
Aluminum(Al) etc.
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Light source
Gold coated film
Bulk liquid
Elastomer
Nanoscale film
Photodetector
Prism
Fig-1: Light (λ) in resonance with surface plasmon resonance

8. Working principle of SPR
 When a light ray incident onto a
metal film at a specific angle, the
surface plasmons are set to resonate
with the light.
 This resonance results in the
absorption of light.
 As a result it presents itself as an
electromagnetic field with resonance
oscillation.
 This resonance oscillation is
denoted as SPR.
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Fig-2: Basic operation of SPR

9. Application of SPR
 Bio-sensing
 Medical diagnostics
 Gas detection
 Environment monitoring
 Real time monitoring and so on…
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10. Merits and Demerits of SPR
 Merits
– Small sample sizes
– Reusable sensor chips
– High efficiency
 Demerits
– SPR equipment is expensive
– Needs expert knowledge to design
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Fig-4

11. Design
 Parameters of this structure :
 Distance between to the centre of two
vicinal air cavities p=1.00 µm
 Regular air hole diameter d1 =.95µm
 Smallest air holes diameter dc=0.15µm
 Thickness of gold layer tg = 20 nm
 Thickness of graphene layer tt = 10 nm
 Thickness of analyte layer ta = 1.2 µm
 Thickness of PML tPML = 1.5 µm
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Fig-5: Cross sectional views of the
proposed circular lattice PCF sensor

12. Methodology
 In this work we use a numerical method which is called finite element method (FEM) .
 Software: COMSOL Multiphysics .
 At first we design the structure.
 Then we add materials in this structure.
 We simulate the structure for different analytes and layer.
 We plotted the simulated data in MICROSOFT EXCEL.
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13. Methodology
Fig 7(a): X-polarization of core mode
Fig 7(d): Y-polarization of SPP mode
Fig 7(b) : Y-polarization of core mode
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Fig 7(c): X-polarization of SPP mode

14. Numerical analysis
 Sellmeier equation is used to obtain the refractive index of fused silica,
n
2
(λ) = 1 +
𝐵1λ2
λ2−𝐶1
+
𝐵2λ2
λ2−𝐶2
+
𝐵3λ2
λ2−𝐶3
(1)
 The confinement loss provides an important role whose parameters can be
achieved by the following equation ,
𝛼 = 8.686 × 𝑘0
. 𝐼𝑚 𝑛𝑒𝑓𝑓 × 104dB/cm (2)
Where, the number of free space is denoted by, k0=2π/λ
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15. Numerical analysis cont…
 To calculate the amplitude sensitivity following equation is used,
SA λ RIU−1 = −
1
α(λ,na)
𝜕α(λ,na)
𝜕na
(3)
 The following equation is used to compute the wavelength sensitivity,
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𝑆λ
nm
RIU =
∆λpeak
∆na
(4)

16. Numerical analysis cont…
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 Wavelength Resolution:
𝑅𝜆=
𝛿𝑛𝑎 × 𝛿𝜆𝑚𝑖𝑛
𝛿𝜆𝑝𝑒𝑎𝑘
(RIU) (5)
Where , 𝛿𝜆𝑚𝑖𝑛 is the minimum spectrul resolution and 𝛿𝜆𝑝𝑒𝑎𝑘 is the resonance wavelength shift .

17. Result analysis and discussion
 The gray line indicates core mode and the orange line indicates SPP mode of the proposed
structure.
 Blue arrow indicates intersect point of SPP mode and core mode.
 At this point maximum resonance is transferred.
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Fig 8: SPP-Core mode dispersion relation at analyte RI of 1.37 for x-polarization and for y-polarization .

18. Result analysis and discussion cont…
 Relative confinement loss variation with different pitch
 Corresponding figure represents that confinement loss varies with the variation of
pitch
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Fig 9 : Confinement loss curves at analyte RI of 1.37 (solid lines) and 1.38 (dashed lines) for p = 1.0µm, 1.05 µm , 1.10 µm

19. Result analysis and discussion cont…
 Amplitude sensitivity for variation of pitch .
 Corresponding figure represents maximum sensitivity for different pitch.
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Fig 10 : Amplitude Sensitivity curves at analyte RI of 1.37 for p = 1.00 µm , 1.05 µm ,1.10 µm

20. Result analysis and discussion cont…
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 Relative confinement loss variation with different different thickness of gold layer
 Corresponding figure represents that confinement loss varies with the variation of gold layer thickness .
Fig 11 : Confinement loss curves at analyte RI of 1.37 (solid lines) and 1.38 (dashed lines) for tg = 15 nm, 20 nm , 25 nm for x-
pol and for y-pol .

21. Result analysis and discussion cont…
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 Amplitude Sensitivity for different different thickness of gold layer
 Corresponding figure represents maximum sensitivity for different gold layer thickness .
Fig 12 : Amplitude Sensitivity curves at analyte RI of 1.37 for tg = 15 nm , 20 nm , 25nm for x-polarization and for y-
polarization .

22. Result analysis and discussion cont…
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 Corresponding figure represents that confinement loss for different analytes from 1.32 to 1.41.
Fig 13 : Confinement loss curves from analyte RI of 1.32 to 1.41 for x-polarization and for y-polarization .

23. Result analysis and discussion cont…
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 Corresponding figure represents maximum sensitivity for different analytes from 1.32 to 1.41.
Fig 14 : Amplitude Sensitivity curves from analyte RI of 1.37 to 1.41 for x-polarization and for y-polarization .

24. Result analysis and discussion cont…
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 A high linearity response of regression line indicates a good sensor.
 The linear fitting curve shows R2 value of 0.9584 which provides a better linearity
Fig-13: Regression line of the resonance wavelength as a function of analyte RI

25. Comparison table
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Table-1 : Comparison of the proposed sensor with recently published articles.
PCF
Sensor
Maximum
amplitude
sensitivity
(RIU-1)
Wavelength
sensitivity
(nm/RIU)
Peak loss (dB/cm)
Ref. 01 80 2000 2500
Ref. 02 118 1000 19.9
Ref. 03 266 2200 160
Ref. 04 47.77 3700 —
Ref. 06 72.47 2520 60
Ref. 08 — 7700 107.11
Ref. 09 — 3200 400
Proposed 822 17000 22.4

26. Future work
 Try to design simple structure
 Try to gain high sensitivity
 Try to reduce confinement loss
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27. Conclusion
 Proposed PCF shows better performance than prior PCF based on SPR
 It shows maximum amplitude sensitivity 318 RIU-1 at wavelength 0.71 µm among analyte 1.34-1.37.
 Proposed structure is very easy to fabricate
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28. References
1. Dash, J.N.; Jha, R. SPR biosensor based on polymer pcf coated with conducting metal oxide. IEEE
Photon. Technol. Lett. 2014, 26, 595–598.
2. Rifat AA, Mahdiraji GA, Shee YG, Shawon MJ, Adikan FM. A novel photonic crystal fiber
biosensor using surface plasmon resonance. Procedia Engineering. 2016 Jan 1;140:1-7.
3. Hasan, M.R.; Akter, S.; Rifat, A.A.; Rana, S.; Ali, S. A Highly Sensitive Gold-Coated Photonic
Crystal Fiber Biosensor Based on Surface Plasmon Resonance. Photonics 2017, 4, 18.
4. M. Y. Azab, M. F. O. Hameed, and S. S. A. Obayya, “Multi-functional optical sensor based on
plasmonic photonic liquid crystal fibers,” Opt. Quantum Electron. 49(2), 49 (2017).
5. S. I. Azzam et al., “Multichannel photonic crystal fiber surface plasmon resonance based sensor,”
Opt. Quantum Electron. 48(2), 142 (2016).
6. X. Yang et al., “Analysis of graphene-based photonic crystal fiber sensor using birefringence and
surface plasmon resonance,” Plasmonics 12(2), 489–496(2017).
7. Z. Tan et al., “Improving the sensitivity of fiber surface plasmon resonance sensor by filling liquid
in a hollow core photonic crystal fiber,”Plasmonics9(1),167–173(2014).
8. R. K. Gangwar and V. K. Singh, “Highly sensitive surface plasmon resonance based D-shaped
photonic crystal fiber refractive index sensor”, Plamonics 1-6(2016).
9. E. K. Akowuah et al., “A highly sensitive photonic crystal fibre (PCF)surface plasmon resonance
(SPR) sensor based on a bimetallic structureof gold and silver,” in Proc. IEEE 4th Int. Conf. on
Adaptive Scienceand Technology, pp. 121–125 (2012).
10. Gupta, B.D.; Verma, R.K. Surface plasmon resonance-based fiber optic sensors: Principle, probe
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