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Optical limiting and enhanced optical nonlinearity in boron-doped carbon nanotubes
| Content Provider | Semantic Scholar |
|---|---|
| Author | Xu, Jianfeng Xiao, Min Yi Czerw, R. Carroll, D. L. |
| Copyright Year | 2004 |
| Abstract | The optical limiting characteristics of pure and boron-doped multi-walled carbon nanotubes (MWNTs) are studied and compared at wavelengths of 532 and 1064 nm. Fluence-dependent transmission and Z-scan measurements using 8 ns pulses show that the boron-doped MWNT suspensions exhibit a stronger optical nonlinearity with fluence than pure carbon nanotube suspensions in both the visible and near-infrared wavelength ranges. The nonlinear response for both materials is dependent on reaggregation within the suspension under study. 2004 Elsevier B.V. All rights reserved. Optical limiting has been an active field of research for the last decade due to growing needs in eye protection from intense laser exposure, as well as for protective applications in optical sensors [1]. While carbon nanotubes are known primarily for their extraordinary electronic and mechanical properties [2,3], researchers have observed strong and broad-band optical limiting in single-walled and multi-walled nanotube suspensions [4,5], as well as in solid nanocomposites [6,7]. There are some important review articles which have made a full coverage on the nonlinear optical properties of (doped) carbon nanotubes [8,9]. Such nonlinear optical transmission in carbon nanotubes has been shown to be strongly dependent on the host media, width and wavelength of light pulses. A general fluence limiting model gaining wide acceptance is as follows. The incoming pulse is quite long at several nanoseconds so the leading edge of the pulse beginning to heat the nanotube rapidly. At the lowest fluences thermal transfer to the solvent leads to the creation of ‘mirco-bubbles.’ However, as the fluence begins to rise, desorption of oxygen, amorphous carbon and other species attached to the nanotube surface begins to dominate thermal energy * Corresponding author. Fax: +1-479-575-4580. E-mail address: phyxujf@hotmail.com (J. Xu). 0009-2614/$ see front matter 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.cplett.2004.03.111 transfer. Finally, at the highest fluences, ablation of the nanotube itself begins to take place forming the socalled ‘micro-plasma’ [10,11]. Scattering becomes nonlinear since the higher light intensity creates more ‘bubbles’ (used in the general context), which cause the transmission to go down. We note that view this will have specific consequences, namely pulse width dependence of the limiting phenomena and pulse repetition rate dependences of the limiting phenomena, both of which are observed. While a simple version of this mechanism has been used to explain optical limiting in carbon black suspensions (the fluence regimes are not as well defined as in the nanotube case because the material ablates more easily), the effect is thought to be enhanced in carbon nanotubes because of their large aspect ratios that allow them to behave as effective antennae. Nonlinear transmission characteristics have also been observed in nanotubes embedded in solids (nanocomposites) or soluble samples [6,7] and the effects are similar to or even stronger than suspension samples. Nonlinear absorption was proposed to explain the strong optical limiting effects in such system, though the effects of heat transfer to the matrix were not broadly addressed in that work [6]. An instructive approach to understanding the various fluence dependent mechanisms involved in optical |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.uark.edu/misc/quantopt/group%20paper/2004/cpl247.pdf |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | Ablation Boron Carbon Black Carbon Monoxide Poisoning Carbon Tetrachloride Doping (semiconductor) Email Embedded system Embedding Fax Heat (physical force) Lightheadedness Like button Multi-Walled Nanotube Nanocomposite Nanotubes Nanotubes, Carbon Nonlinear system Numerous Occur (action) Oxygen Pulse-width modulation Suspensions The Matrix sensor (device) solid substance wavelength width |
| Content Type | Text |
| Resource Type | Article |
