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Ultrasensitive optical absorption in graphene based on bound states in the continuum.

Zhang M, Zhang X - Sci Rep (2015)

Bottom Line: By taking suitable BICs, the selective absorption for S and P waves has not only been realized, but also all-angle absorption for the S and P waves at the same time has been demonstrated.We have also found that ultrasensitive strong absorptions can appear at any wavelength from mid-infrared to far-infrared band.These phenomena are very beneficial to biosensing, perfect filters and waveguides.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, Beijing Normal University, Beijing 100875, China.

ABSTRACT
We have designed a sphere-graphene-slab structure so that the electromagnetic wave can be well confined in the graphene due to the formation of a bound state in a continuum (BIC) of radiation modes. Based on such a bound state, we have realized strong optical absorption in the monolayer graphene. Such a strong optical absorption exhibits many advantages. It is ultrasensitive to the wavelength because the Q factor of the absorption peak can be more than 2000. By taking suitable BICs, the selective absorption for S and P waves has not only been realized, but also all-angle absorption for the S and P waves at the same time has been demonstrated. We have also found that ultrasensitive strong absorptions can appear at any wavelength from mid-infrared to far-infrared band. These phenomena are very beneficial to biosensing, perfect filters and waveguides.

No MeSH data available.


Distributions of the electric field intensity in the sphere-graphene-slab structure at the resonant absorption case.Here λ = 15 μm, a = 5.5185 μm, r = 0.3a and D = 0.3a. The other parameters are identical with those in Fig. 1. (a) Distributions of the electric field intensity in the XZ-plane at Y = 0. (b) Distributions of the electric field intensity in the XY-plane for one primitive cell with Z = 0.5, Z = 0.8, Z = 1.1 and Z = 1.39.
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f3: Distributions of the electric field intensity in the sphere-graphene-slab structure at the resonant absorption case.Here λ = 15 μm, a = 5.5185 μm, r = 0.3a and D = 0.3a. The other parameters are identical with those in Fig. 1. (a) Distributions of the electric field intensity in the XZ-plane at Y = 0. (b) Distributions of the electric field intensity in the XY-plane for one primitive cell with Z = 0.5, Z = 0.8, Z = 1.1 and Z = 1.39.

Mentions: In order to disclose physical origin of the above phenomenon, in Fig. 3 we plot the distributions of the electric field intensity in the structure at the resonant absorption, which correspond to the resonant absorption peak at λ = 15 μm in Fig. 2(b). Figure 3(a) and (b) show the electric field intensity patterns in XZ-plane at Y = 0 and XY-plane for one primitive cell with various Z, respectively. The distributions of the electric field in the structure is very similar to that shown in Fig. 1(b), although the monolayer graphene has been put in the double-layer structure. We can see the maximum of field intensity appears in the graphene layer by the formation of BICs, which leads to strong interaction between the EM field and the graphene. This is the reason why there is such a strong absorption for the monolayer graphene in the present structure.


Ultrasensitive optical absorption in graphene based on bound states in the continuum.

Zhang M, Zhang X - Sci Rep (2015)

Distributions of the electric field intensity in the sphere-graphene-slab structure at the resonant absorption case.Here λ = 15 μm, a = 5.5185 μm, r = 0.3a and D = 0.3a. The other parameters are identical with those in Fig. 1. (a) Distributions of the electric field intensity in the XZ-plane at Y = 0. (b) Distributions of the electric field intensity in the XY-plane for one primitive cell with Z = 0.5, Z = 0.8, Z = 1.1 and Z = 1.39.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4317701&req=5

f3: Distributions of the electric field intensity in the sphere-graphene-slab structure at the resonant absorption case.Here λ = 15 μm, a = 5.5185 μm, r = 0.3a and D = 0.3a. The other parameters are identical with those in Fig. 1. (a) Distributions of the electric field intensity in the XZ-plane at Y = 0. (b) Distributions of the electric field intensity in the XY-plane for one primitive cell with Z = 0.5, Z = 0.8, Z = 1.1 and Z = 1.39.
Mentions: In order to disclose physical origin of the above phenomenon, in Fig. 3 we plot the distributions of the electric field intensity in the structure at the resonant absorption, which correspond to the resonant absorption peak at λ = 15 μm in Fig. 2(b). Figure 3(a) and (b) show the electric field intensity patterns in XZ-plane at Y = 0 and XY-plane for one primitive cell with various Z, respectively. The distributions of the electric field in the structure is very similar to that shown in Fig. 1(b), although the monolayer graphene has been put in the double-layer structure. We can see the maximum of field intensity appears in the graphene layer by the formation of BICs, which leads to strong interaction between the EM field and the graphene. This is the reason why there is such a strong absorption for the monolayer graphene in the present structure.

Bottom Line: By taking suitable BICs, the selective absorption for S and P waves has not only been realized, but also all-angle absorption for the S and P waves at the same time has been demonstrated.We have also found that ultrasensitive strong absorptions can appear at any wavelength from mid-infrared to far-infrared band.These phenomena are very beneficial to biosensing, perfect filters and waveguides.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, Beijing Normal University, Beijing 100875, China.

ABSTRACT
We have designed a sphere-graphene-slab structure so that the electromagnetic wave can be well confined in the graphene due to the formation of a bound state in a continuum (BIC) of radiation modes. Based on such a bound state, we have realized strong optical absorption in the monolayer graphene. Such a strong optical absorption exhibits many advantages. It is ultrasensitive to the wavelength because the Q factor of the absorption peak can be more than 2000. By taking suitable BICs, the selective absorption for S and P waves has not only been realized, but also all-angle absorption for the S and P waves at the same time has been demonstrated. We have also found that ultrasensitive strong absorptions can appear at any wavelength from mid-infrared to far-infrared band. These phenomena are very beneficial to biosensing, perfect filters and waveguides.

No MeSH data available.