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Single Nanoparticle Detection Using Far-field Emission of Photonic Molecule around the Exceptional Point.

Zhang N, Liu S, Wang K, Gu Z, Li M, Yi N, Xiao S, Song Q - Sci Rep (2015)

Bottom Line: In addition to typical mode splitting, we find that the far-field pattern of the PM is significantly changed.Taking a heteronuclear diatomic PM as an example, we demonstrate that a single nanoparticle, whose radius is as small as 1 nm to 7 nm, can be simply monitored through the variation of the far-field pattern.In addition, this research will illuminate new advances in single nanoparticle detection.

View Article: PubMed Central - PubMed

Affiliation: Integrated Nanoscience Lab, Department of Electrical and Information Engineering, Harbin Institute of Technology, Shenzhen, 518055, China.

ABSTRACT
Highly sensitive, label-free detection methods have important applications in fundamental research and healthcare diagnostics. To date, the detection of single nanoparticles has remained largely dependent on extremely precise spectral measurement, which relies on high-cost equipment. Here, we demonstrate a simple but very nontrivial mechanism for the label-free sizing of nanoparticles using the far-field emission of a photonic molecule (PM) around an exceptional point (EP). By attaching a nanoparticle to a PM around an EP, the main resonant behaviors are strongly disturbed. In addition to typical mode splitting, we find that the far-field pattern of the PM is significantly changed. Taking a heteronuclear diatomic PM as an example, we demonstrate that a single nanoparticle, whose radius is as small as 1 nm to 7 nm, can be simply monitored through the variation of the far-field pattern. Compared with conventional methods, our approach is much easier and does not rely on high-cost equipment. In addition, this research will illuminate new advances in single nanoparticle detection.

No MeSH data available.


Related in: MedlinePlus

(a) The U−30°−70° as a function of radius of nanoparticle at different positions. (b) The corresponding directional output in angle range 280–287 degree as a function of r2. With these two curves, the position dependence of detection can be eliminated.
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f5: (a) The U−30°−70° as a function of radius of nanoparticle at different positions. (b) The corresponding directional output in angle range 280–287 degree as a function of r2. With these two curves, the position dependence of detection can be eliminated.

Mentions: The above analysis and numerical results show that the variation in the far-field pattern might be a way to detect nanoparticles. This technique does not require the ultrahigh Q factor and extremely fine spectral resolution that are necessary for the conventional method. There is one remaining technical challenge in detection. As shown in Eq. (3), the influence of the external nanoparticle clearly shows position dependence. Figure 5(a) demonstrates the corresponding numerical results at different angles. We find that the U−30°−70° factors with the target particle at the azimuthal angle β = 0, π/2, π are almost the same, and U−30°−70° with the particle at the azimuthal angle β = π/4 and 3π/4 are also very close. However, the curves at β = 0 and β = π/4 are quite different, especially in the range r2 > 3 nm. The U−30°−70° factors at other β values fall between them. This type of deviation is consistent with Eq. (3) and results from the interaction between scattered waves from the nanoparticle and annular cavity32. Because the azimuthal number is 10, β = 0, π/2, π give the same value in Eq. (3), as do β = π/4 and 3π/4. Therefore, the deviation induces unexpected inaccuracy. For example, the U−30°−70° factors with (β = 0, r2 = 4 nm) and (β = π/4, r2 = 6 nm) are very close in Fig. 5(a).


Single Nanoparticle Detection Using Far-field Emission of Photonic Molecule around the Exceptional Point.

Zhang N, Liu S, Wang K, Gu Z, Li M, Yi N, Xiao S, Song Q - Sci Rep (2015)

(a) The U−30°−70° as a function of radius of nanoparticle at different positions. (b) The corresponding directional output in angle range 280–287 degree as a function of r2. With these two curves, the position dependence of detection can be eliminated.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493635&req=5

f5: (a) The U−30°−70° as a function of radius of nanoparticle at different positions. (b) The corresponding directional output in angle range 280–287 degree as a function of r2. With these two curves, the position dependence of detection can be eliminated.
Mentions: The above analysis and numerical results show that the variation in the far-field pattern might be a way to detect nanoparticles. This technique does not require the ultrahigh Q factor and extremely fine spectral resolution that are necessary for the conventional method. There is one remaining technical challenge in detection. As shown in Eq. (3), the influence of the external nanoparticle clearly shows position dependence. Figure 5(a) demonstrates the corresponding numerical results at different angles. We find that the U−30°−70° factors with the target particle at the azimuthal angle β = 0, π/2, π are almost the same, and U−30°−70° with the particle at the azimuthal angle β = π/4 and 3π/4 are also very close. However, the curves at β = 0 and β = π/4 are quite different, especially in the range r2 > 3 nm. The U−30°−70° factors at other β values fall between them. This type of deviation is consistent with Eq. (3) and results from the interaction between scattered waves from the nanoparticle and annular cavity32. Because the azimuthal number is 10, β = 0, π/2, π give the same value in Eq. (3), as do β = π/4 and 3π/4. Therefore, the deviation induces unexpected inaccuracy. For example, the U−30°−70° factors with (β = 0, r2 = 4 nm) and (β = π/4, r2 = 6 nm) are very close in Fig. 5(a).

Bottom Line: In addition to typical mode splitting, we find that the far-field pattern of the PM is significantly changed.Taking a heteronuclear diatomic PM as an example, we demonstrate that a single nanoparticle, whose radius is as small as 1 nm to 7 nm, can be simply monitored through the variation of the far-field pattern.In addition, this research will illuminate new advances in single nanoparticle detection.

View Article: PubMed Central - PubMed

Affiliation: Integrated Nanoscience Lab, Department of Electrical and Information Engineering, Harbin Institute of Technology, Shenzhen, 518055, China.

ABSTRACT
Highly sensitive, label-free detection methods have important applications in fundamental research and healthcare diagnostics. To date, the detection of single nanoparticles has remained largely dependent on extremely precise spectral measurement, which relies on high-cost equipment. Here, we demonstrate a simple but very nontrivial mechanism for the label-free sizing of nanoparticles using the far-field emission of a photonic molecule (PM) around an exceptional point (EP). By attaching a nanoparticle to a PM around an EP, the main resonant behaviors are strongly disturbed. In addition to typical mode splitting, we find that the far-field pattern of the PM is significantly changed. Taking a heteronuclear diatomic PM as an example, we demonstrate that a single nanoparticle, whose radius is as small as 1 nm to 7 nm, can be simply monitored through the variation of the far-field pattern. Compared with conventional methods, our approach is much easier and does not rely on high-cost equipment. In addition, this research will illuminate new advances in single nanoparticle detection.

No MeSH data available.


Related in: MedlinePlus