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Study of nanostructure growth with nanoscale apex induced by femtosecond laser irradiation at megahertz repetition rate.

Patel NB, Tan B, Venkatakrishnan K - Nanoscale Res Lett (2013)

Bottom Line: We have recently developed this unique technique to grow leaf-like nanostructures with such interesting geometry without the use of any catalyst.It was found to be possible only in the presence of background nitrogen gas flow.We observed a clear transformation in the kind of nanotips that grew for the given laser conditions.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Aerospace Engineering, Ryerson University, Victoria Street, Toronto, ON M5B 2K3, Canada. tanbo@ryerson.ca.

ABSTRACT
Leaf-like nanostructures with nanoscale apex are induced on dielectric target surfaces by high-repetition-rate femtosecond laser irradiation in ambient conditions. We have recently developed this unique technique to grow leaf-like nanostructures with such interesting geometry without the use of any catalyst. It was found to be possible only in the presence of background nitrogen gas flow. In this synthesis method, the target serves as the source for building material as well as the substrate upon which these nanostructures can grow. In our investigation, it was found that there are three possible kinds of nanotips that can grow on target surfaces. In this report, we have presented the study of the growth mechanisms of such leaf-like nanostructures under various conditions such as different laser pulse widths, pulse repetition rates, dwell times, and laser polarizations. We observed a clear transformation in the kind of nanotips that grew for the given laser conditions.

No MeSH data available.


Related in: MedlinePlus

Comparison of nanotip growth under different polarizations of laser pulses. SEM images of the glass target irradiated with circularly polarized pulses (a, b, c) and linearly (p-) polarized laser pulses (d, e, f); (a, d) 4 MHz, 0.25 ms; (b, e) 4 MHz, 0.5 ms; (c, f) 8 MHz, 0.25 ms; the pulse width used for all experiments was 214 fs.
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Figure 10: Comparison of nanotip growth under different polarizations of laser pulses. SEM images of the glass target irradiated with circularly polarized pulses (a, b, c) and linearly (p-) polarized laser pulses (d, e, f); (a, d) 4 MHz, 0.25 ms; (b, e) 4 MHz, 0.5 ms; (c, f) 8 MHz, 0.25 ms; the pulse width used for all experiments was 214 fs.

Mentions: In our investigation, we found results that support the findings in the aforementioned investigation performed by other researchers. We found that when the glass was irradiated by p-polarized laser pulses, a much larger number of nanotips were found to be growing for the same parameters in comparison to circularly polarized pulses, as depicted in Figure 10. It was found by other researchers that the p-polarized laser pulses ablate the target material at fluences much smaller than the ablation threshold fluence for circular polarization. If this is true, then the p-polarized pulses remove material much more efficiently with much fewer pulses in comparison to circularly polarized laser pulses. In other words, the growth stages explained in Figure 8 must be occurring in the fast-forwarding mode during linearly polarized laser ablation.


Study of nanostructure growth with nanoscale apex induced by femtosecond laser irradiation at megahertz repetition rate.

Patel NB, Tan B, Venkatakrishnan K - Nanoscale Res Lett (2013)

Comparison of nanotip growth under different polarizations of laser pulses. SEM images of the glass target irradiated with circularly polarized pulses (a, b, c) and linearly (p-) polarized laser pulses (d, e, f); (a, d) 4 MHz, 0.25 ms; (b, e) 4 MHz, 0.5 ms; (c, f) 8 MHz, 0.25 ms; the pulse width used for all experiments was 214 fs.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3643873&req=5

Figure 10: Comparison of nanotip growth under different polarizations of laser pulses. SEM images of the glass target irradiated with circularly polarized pulses (a, b, c) and linearly (p-) polarized laser pulses (d, e, f); (a, d) 4 MHz, 0.25 ms; (b, e) 4 MHz, 0.5 ms; (c, f) 8 MHz, 0.25 ms; the pulse width used for all experiments was 214 fs.
Mentions: In our investigation, we found results that support the findings in the aforementioned investigation performed by other researchers. We found that when the glass was irradiated by p-polarized laser pulses, a much larger number of nanotips were found to be growing for the same parameters in comparison to circularly polarized pulses, as depicted in Figure 10. It was found by other researchers that the p-polarized laser pulses ablate the target material at fluences much smaller than the ablation threshold fluence for circular polarization. If this is true, then the p-polarized pulses remove material much more efficiently with much fewer pulses in comparison to circularly polarized laser pulses. In other words, the growth stages explained in Figure 8 must be occurring in the fast-forwarding mode during linearly polarized laser ablation.

Bottom Line: We have recently developed this unique technique to grow leaf-like nanostructures with such interesting geometry without the use of any catalyst.It was found to be possible only in the presence of background nitrogen gas flow.We observed a clear transformation in the kind of nanotips that grew for the given laser conditions.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Aerospace Engineering, Ryerson University, Victoria Street, Toronto, ON M5B 2K3, Canada. tanbo@ryerson.ca.

ABSTRACT
Leaf-like nanostructures with nanoscale apex are induced on dielectric target surfaces by high-repetition-rate femtosecond laser irradiation in ambient conditions. We have recently developed this unique technique to grow leaf-like nanostructures with such interesting geometry without the use of any catalyst. It was found to be possible only in the presence of background nitrogen gas flow. In this synthesis method, the target serves as the source for building material as well as the substrate upon which these nanostructures can grow. In our investigation, it was found that there are three possible kinds of nanotips that can grow on target surfaces. In this report, we have presented the study of the growth mechanisms of such leaf-like nanostructures under various conditions such as different laser pulse widths, pulse repetition rates, dwell times, and laser polarizations. We observed a clear transformation in the kind of nanotips that grew for the given laser conditions.

No MeSH data available.


Related in: MedlinePlus