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Tunable potential well for plasmonic trapping of metallic particles by bowtie nano-apertures

View Article: PubMed Central - PubMed

ABSTRACT

In this paper, the tunable optical trapping dependence on wavelength of incident beam is theoretically investigated based on numerical simulations. The Monte Carlo method is taken into account for exploring the trapping characteristics such as average deviation and number distribution histogram of nanoparticles. It is revealed that both the width and the depth of potential well for trapping particles can be flexibly adjusted by tuning the wavelength of the incident beam. In addition, incident wavelengths for the deepest potential well and for the strongest stiffness at bottom are separated. These phenomena are explained as the strong plasmon coupling between tweezers and metallic nanoparticles. In addition, required trapping fluence and particles’ distributions show distinctive properties through carefully modifying the incident wavelengths from 1280 nm to 1300 nm. Trapping with lowest laser fluence can be realized with1280 nm laser and trapping with highest precision can be realized with 1300 nm laser. This work will provide theoretical support for advancing the manipulation of metallic particles and related applications such as single-molecule fluorescence and surface enhanced Raman spectroscopy.

No MeSH data available.


Potential well and number distribution histograms of the trapped particles with laser fluence of (a) 2.8 × 108 W/m2 and (b) 5.6 × 108 W/m2. The blue line and bars represent the simulated data acquired by 1280 nm laser and the red line and bars represent the simulated data acquired by 1300 nm laser. The particle size is 50 nm. The media temperature applied in the simulation is 300 kT.
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f5: Potential well and number distribution histograms of the trapped particles with laser fluence of (a) 2.8 × 108 W/m2 and (b) 5.6 × 108 W/m2. The blue line and bars represent the simulated data acquired by 1280 nm laser and the red line and bars represent the simulated data acquired by 1300 nm laser. The particle size is 50 nm. The media temperature applied in the simulation is 300 kT.

Mentions: The number distribution histograms of trapped particles and the shape of trapping potential wells under the laser power of 2.8 × 108 W/m2 and 5.6 × 108 W/m2 are shown in Fig. 5(a,b), in which the wavelength of 1280 nm and 1300 nm are applied. With the fluence of 2.8 × 108 W/m2, the depth of the potential well is minus 8.7 kT for the 1280 nm laser and minus 6.5 kT for the 1300 nm laser. As a result, the total number of the trapped particles form −40 nm to 40 nm is 14778 for the 1280 nm laser and 10101 for the 1300 nm laser. Nearly all of the nanoparticles can be trapped with1280 nm laser and only 67% of nanoparticles can be trapped by 1300 nm laser. The trapped particles are more concentrated to the center of tweezers when irradiated by the 1300 nm laser, which could also be attributed to the strong stiffness and narrow potential well width existing in long wavelength range. At the fluence of 5.6 × 108 W/m2, the depth of the potential well is minus 17.5 kT for the 1280 nm laser and minus 13 kT for the 1300 nm laser, correspondently, 15000 particles are trapped for 1280 nm laser and 14998 particles are trapped for 1300 nm laser. Nearly all of the particles can be trapped with both kind of wavelength because both of the potential wells are deep enough to realize stable trapping. Compared with 1280 nm laser, much more particles could concentratearound the center of the tweezers, indicating a much more precise control of the trapped particles.


Tunable potential well for plasmonic trapping of metallic particles by bowtie nano-apertures
Potential well and number distribution histograms of the trapped particles with laser fluence of (a) 2.8 × 108 W/m2 and (b) 5.6 × 108 W/m2. The blue line and bars represent the simulated data acquired by 1280 nm laser and the red line and bars represent the simulated data acquired by 1300 nm laser. The particle size is 50 nm. The media temperature applied in the simulation is 300 kT.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5036050&req=5

f5: Potential well and number distribution histograms of the trapped particles with laser fluence of (a) 2.8 × 108 W/m2 and (b) 5.6 × 108 W/m2. The blue line and bars represent the simulated data acquired by 1280 nm laser and the red line and bars represent the simulated data acquired by 1300 nm laser. The particle size is 50 nm. The media temperature applied in the simulation is 300 kT.
Mentions: The number distribution histograms of trapped particles and the shape of trapping potential wells under the laser power of 2.8 × 108 W/m2 and 5.6 × 108 W/m2 are shown in Fig. 5(a,b), in which the wavelength of 1280 nm and 1300 nm are applied. With the fluence of 2.8 × 108 W/m2, the depth of the potential well is minus 8.7 kT for the 1280 nm laser and minus 6.5 kT for the 1300 nm laser. As a result, the total number of the trapped particles form −40 nm to 40 nm is 14778 for the 1280 nm laser and 10101 for the 1300 nm laser. Nearly all of the nanoparticles can be trapped with1280 nm laser and only 67% of nanoparticles can be trapped by 1300 nm laser. The trapped particles are more concentrated to the center of tweezers when irradiated by the 1300 nm laser, which could also be attributed to the strong stiffness and narrow potential well width existing in long wavelength range. At the fluence of 5.6 × 108 W/m2, the depth of the potential well is minus 17.5 kT for the 1280 nm laser and minus 13 kT for the 1300 nm laser, correspondently, 15000 particles are trapped for 1280 nm laser and 14998 particles are trapped for 1300 nm laser. Nearly all of the particles can be trapped with both kind of wavelength because both of the potential wells are deep enough to realize stable trapping. Compared with 1280 nm laser, much more particles could concentratearound the center of the tweezers, indicating a much more precise control of the trapped particles.

View Article: PubMed Central - PubMed

ABSTRACT

In this paper, the tunable optical trapping dependence on wavelength of incident beam is theoretically investigated based on numerical simulations. The Monte Carlo method is taken into account for exploring the trapping characteristics such as average deviation and number distribution histogram of nanoparticles. It is revealed that both the width and the depth of potential well for trapping particles can be flexibly adjusted by tuning the wavelength of the incident beam. In addition, incident wavelengths for the deepest potential well and for the strongest stiffness at bottom are separated. These phenomena are explained as the strong plasmon coupling between tweezers and metallic nanoparticles. In addition, required trapping fluence and particles’ distributions show distinctive properties through carefully modifying the incident wavelengths from 1280 nm to 1300 nm. Trapping with lowest laser fluence can be realized with1280 nm laser and trapping with highest precision can be realized with 1300 nm laser. This work will provide theoretical support for advancing the manipulation of metallic particles and related applications such as single-molecule fluorescence and surface enhanced Raman spectroscopy.

No MeSH data available.