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Non-Linear Optical Properties of Nano Particle C60 Fullerene Using Lasers
ISSN: 2469-410X

Journal of Lasers, Optics & Photonics
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Non-Linear Optical Properties of Nano Particle C60 Fullerene Using Lasers

Subramaniam TK1*, Vinitha G2, Jayakumar CV1 and Premanand R1
1Sri Sairam Engineering College, Chennai, India
2Vellore Institute of Technology, Chennai, India
*Corresponding Author: Subramaniam TK, Sri Sairam Engineering College, Sairam Campus, Sai Leo Nagar, West Tambaram, 600044, Chennai, Tamil Nadu, India, Tel: 044-2251 2222, Email: [email protected]

Received Date: Apr 06, 2018 / Accepted Date: Apr 18, 2018 / Published Date: Apr 25, 2018

Abstract

The third order non-linear optical properties of Buckminster fullerene (C60) molecule has been studied using a Nd:YAG laser, in the visible and in the infrared region. The solvent using toluene was specifically used because of low threshold intensity for an optical limiter application. Closed aperture Z-scan technique was adopted to characterize the material due to its simplicity and high sensitivity in measuring the third-order optical nonlinearity. This allows computing the contributions of nonlinear absorption and nonlinear refraction towards nonlinearity. Saturable Absorption (SA) for C60 nano particles is also established. RSA is not established. FT-IR studies is also carried out to characterize the sample and to correlate the NLO studies.

Keywords: Buckminster fullerene; Non-linear properties; Visible and infrared regions; Nd: YAG laser; Third order NLO property; Optical limiter; Non-linear refraction

Introduction

Nanotechnology plays an important role in finding new nano scale materials for the benefit of renewable energies. Nano structured materials are mainly used in applications such as hydrogen and methane storage, fuel cells, solar cells, bio-fuel cells, rechargeable batteries, super capacitors, electrodes, catalysts, gas sensors and other applications. For developing new or novel materials, it is required to synthesize, fabricate, characterize and process these nano materials for any specific application. One such study is the non-linear optical property (NLO) of this C60, Buckminsterfullerene nano particles. The C60 molecule was discovered by Zhou et al. [1] during conduction of an experiment involving graphite under an inert atmosphere of helium. C60 and other such similar structures are considered as promising nonlinear optical materials due to its non-linear refraction and scattering process which is a necessary property for optical limitation.

An optical limiter is a device that will have high transmission of low input signal and for large input signal there will be constant output signal. For example, an intense laser or a light beam can damage the eye. So by using properly designed lenses, one can protect the eye. The other application of NLO property is in shaping of short laser pulses. Simplicity and a fast response time is the main reason for choosing NLO property of C60 material. Saturable absorption, also known as SA is the well-known mechanism for optical limiting devices.SA is applicable for molecular systems because the excited state cross-sectionex is larger than the ground state cross-sectiong which is an ideal situation for an optical limiter application. There are a several characterization techniques available for measuring the third-order optical nonlinearities these includes degenerate four-wave mixing, nearly degenerate three-wave mixing, optical Kerr effect, ellipse rotation, interferometric methods, two beam coupling, beam self-bending and third harmonic generation [2]. Among the available techniques z-scan technique offers simplicity as well as very high sensitivity in measuring the third-order optical nonlinearity and also allows computing the contributions of nonlinear absorption and nonlinear refraction towards the nonlinearity. Z-scan technique is based on the principle of spatial beam distortion. It was originally proposed by Sheik-Bahae, has been since then implemented and applied to the study of third-order optical nonlinearity. Using z-scan technique, the magnitude of nonlinear absorption and the sign and magnitude of nonlinear refraction can be determined simultaneously. When a high intensity laser beam propagates through a material, induced refractive index changes leads to self-focusing or defocusing of the laser beam. This enables to determine the third-order nonlinear optical properties of various materials in liquid, thin film or crystal forms. In this technique, the sample under investigation is moved along the tightly focused Gaussian laser beam. The intensity of the laser beam changes as the sample is moved. This is because the sample experiences different intensities, depending on the position of the sample relative to focus (z=0). The power transmitted through the sample is measured by translating the sample along the z-direction through the beam waist of a focused beam and hence the name z-scan.

Experiment

We obtained a pure research grade 99.999% pure M/s.Merck Co.Ltd. for the analysis of C60 nanoparticles.Initially we tried to record the second order optical non-linearity of the C60 fullerene molecule with the help of a Nd: YAG pulsed laser with wavelength equal to 1.064 micrometre. But the sample did not show any absorption as the IR beam did not pass through it. The IR light was reflected back from the sample without any absorption and so it is reported that there is no second order optical non-linearity for this sample. Thereafter, we proceeded to do the Z-scan experiment to study the third order optical non-linearity using a Nd: YAG laser with a second harmonic output wavelength of 532 nm [3].

Since fullerene molecule shows high volatility it is dissolved in solution to perform NLO studies and so, the C60 nano particles were dissolved in a solvent toluene with a transmittance of 64%. The reason to choose toluene is that it gives a low threshold intensity, to be used as an optical limiter, than any other solution like carbon-black, chloronapthalene etc [4].The sample cell was kept in front of a Nd:YAG laser using 532 nm second-harmonic generated beam in the visible region, for the study of third order NLO properties. The experimental set-up is shown here below in Figure 1 and the schematic of the z-scan experimental set up is shown in Figure 2 below.

lasers-optics-photonics-laser

Figure 1: Z-scan set up using Nd: YAG laser as a source of light.

lasers-optics-photonics-experimental

Figure 2: Schematic of the Z-scan experimental set-up using a Nd: YAG laser.

The characterization of the sample was also done using the FT-IR for percentage of transmission of the C60 molecule and it was found that the sample showed highest transmission (reference is 4000 cm-1 at 100%), (97.8%) at 450 cm-1 (0.002222 cm wavelength) and the lowest transmission percentage (5%) at 1426 cm-1 (0.00070126 cm wavelength), indicating that at the lower wavelength, the sample has low percentage of transmittance and at higher wavelength it has high percentage of transmittance. Thus the third order nonlinear refractive index property can be observed at higher wavelengths due to high transmittance of light in the visible region [4]. The FT-IR spectrum recorded is shown below in Figure 3, (Table 1).

lasers-optics-photonics-recorded

Figure 3: FT-IR transmission spectrum of C60 recorded between 450 cm to 4000 cm-1.

1/l(cm-1) %Transmittance
492.000000 55.9774
491.000000 57.1641
490.000000 58.3859
489.000000 59.6555
488.000000 60.99971
487.000000 62.44777
486.000000 63.99795
485.000000 65.60268
484.000000 67.19168
483.000000 68.71644
482.000000 70.17152
481.000000 71.56383
480.000000 72.89073
479.000000 74.15598
478.000000 75.38279
477.000000 76.60604
476.000000 77.85104
475.000000 79.11794
474.000000 80.38951
473.000000 81.64969
472.000000 82.89004
471.000000 84.10621
470.000000 85.29494
469.000000 86.45373
468.000000 87.58083
467.000000 88.67436
466.000000 89.73207
465.000000 90.75125
464.000000 91.72814
463.000000 92.65752
462.000000 93.53251
461.000000 94.34452
460.000000 95.08398
459.000000 95.74079
458.000000 96.30546
457.000000 96.7717
456.000000 97.13885
455.000000 97.4127
454.000000 97.60391
453.000000 97.72556
452.000000 97.79342
451.000000 97.8248
450.000000 97.83732
1464.000000 7.169664
1463.000000 7.137567
1462.000000 7.102927
1461.000000 7.065651
1460.000000 7.025616
1459.000000 6.982962
1458.000000 6.938173
1457.000000 6.891164
1456.000000 6.841555
1455.000000 6.789933
1454.000000 6.736916
1453.000000 6.682667
1452.000000 6.627128
1451.000000 6.570048
1450.000000 6.511411
1449.000000 6.451523
1448.000000 6.390528
1447.000000 6.328339
1446.000000 6.265105
1445.000000 6.201242
1444.000000 6.137536
1443.000000 6.075523
1442.000000 6.016985
1441.000000 5.962674
1440.000000 5.911109
1439.000000 5.857932
1438.000000 5.795723
1437.000000 5.714539
1436.000000 5.603435
1435.000000 5.453477
1434.000000 5.260926
1433.000000 5.028564
1432.000000 4.765842
1431.000000 4.489079
1430.000000 4.220649
1429.000000 3.984898
1428.000000 3.801625
1427.000000 3.681865
1426.000000 3.627782
1425.000000
1424.000000
3.690331
3.690331
1423.000000 3.780523
1422.000000 3.888246
1421.000000 3.999439
1420.000000 4.104804
1419.000000 4.199532
1418.000000 4.282075
1417.000000 4.353808
1416.000000 4.418198
1415.000000 4.478963
1414.000000 4.538774
1413.000000 4.598907
1412.000000 4.659609
1411.000000 4.720651

Table 1: below gives data related to minimum and maximum percentage transmission of a FT-IR spectrum recorded for C60 molecule.

The recorded parameters for the C60 fullerene molecules during our experiment are, namely, Kerr nonlinearity is found to be (n2)=5.38 x 10-8 cm2/W,

Two-photon absorption coefficient TPA (β)=0.04 × 10-4 cm/W,

Linear refractive index (n0)=1.13, third order electric susceptibility Re (χ3)=1.73 × 10-6 esu,

Imaginary part of the third order electric susceptibility Im (χ3)=0.42 × 10-6 esu, third order electric susceptibility (χ3)=1.79 × 10-6 esu. The Table 2 gives the details as shown below.

n2 x 10-8 cm2/W β x 10-4 cm/W n0 Re χ(3) x 10-6 esu Im χ(3) x 10-6 esu χ(3) x 10-6 esu
5.38 0.07 1.13 1.73 0.42 1.79

Table 2: C60 fullerene molecule- recorded parameters during z-scan experiment

It is seen from the Table 2 above that the contributions of nonlinear absorption (β) and nonlinear refraction (n2) towards nonlinearity is established [5-10]. The laser intensity dependent refractive index in the third order, namely, (χ3) has been prominent, showing negative signs for the absorptive nonlinearities. We attribute this negativity to saturable absorption [11,12]. This shows that C60 Fullerene nano particle is suitable for an optical limiting device, plasmon waveguide, sensor protection, medicine, and nano probes.

A graphical plot and a comparison between closed aperture and open aperture experiment and also the ratio between the two types is shown below.

From the graph seen in Figures 4 and 5, it is seen that linear absorption coefficient has been steadily increasing from the centre on both sides, with the distance of z scan from the centre of the cell in which the solvent is kept. From the Figure 6, we can infer that the solubility in toluene is complete and the sample has shown more transmittance towards the centre of the cell and hence this non-linear refractive index property will be suitable to act as an optical limiter for C60 nano particles. The data from which the graph has been plotted is shown in Table 3 below.

lasers-optics-photonics-aperture

Figure 4: Graph plot for open aperture in C60 z scan.

lasers-optics-photonics-scan

Figure 5: Graph plot for closed aperture in C60 z scan.

lasers-optics-photonics-closed

Figure 6: Ration between closed and open aperture for C60 z scan.

Linear Abs. Co. Closed Open Ratio
-12.5 0.9999 0.999999 0.999901
-12 0.9999 0.999999 0.999901
-11.5 0.9999 0.999999 0.999901
-11 0.9999 0.999999 0.999901
-10.5 0.9999 0.999999 0.999901
-10 0.9999 0.999999 0.999901
-9.5 1.00427 0.999999 1.004271
-9 1.00555 0.999999 1.005551
-8.5 1.012104 1.004621 1.007448
-8 1.016305 1.011863 1.00439
-7.5 1.021907 1.021484 1.000413
-7 1.03211 1.029306 1.002725
-6.5 1.031523 1.035471 0.996188
-6 1.044799 1.041777 1.0029
-5.5 1.057986 1.049689 1.007905
-5 1.065396 1.0559 1.008994
-4.5 1.086287 1.06259 1.022301
-4 1.133863 1.068322 1.061349
-3.5 1.184152 1.074534 1.102015
-3 1.285656 1.081074 1.189239
-2.5 1.431878 1.086574 1.317791
-2 1.459786 1.091766 1.337087
-1.5 1.326546 1.096317 1.210003
-1 1.18136 1.10076 1.073223
-0.5 0.972474 1.104559 0.880419
0 0.615292 1.104399 0.557129
0.5 0.4092 1.098236 0.372598
1 0.283165 1.08956 0.25989
1.5 0.188756 1.080745 0.174654
2 0.219205 1.072832 0.204324
2.5 0.297436 1.065832 0.279064
3 0.357654 1.0559 0.33872
3.5 0.459391 1.049689 0.437645
4 0.518974 1.043727 0.497232
4.5 0.572906 1.037267 0.552323
5 0.615473 1.031055 0.596935
5.5 0.686587 1.024844 0.669943
6 0.764568 1.018633 0.750582
6.5 0.815384 1.012422 0.80538
7 0.87584 1.006211 0.870434
7.5 0.917654 1.002987 0.914921
8 0.958749 0.999999 0.958749
8.5 0.976544 0.999999 0.976544
9 0.9999 0.999999 0.999901
9.5 0.9999 0.999999 0.999901
10 0.9999 0.999999 0.999901
10.5 0.9999 0.999999 0.999901
11 0.9999 0.999999 0.999901
11.5 0.9999 0.999999 0.999901
12 0.9999 0.999999 0.999901
12.5 0.9999 0.999999 0.999901

Table 3: Data on linear absorption coefficient, closed, open apertures and their ratio.

Result and Discussion

For the C60 nano particles, closed aperture Z-scan technique was adopted to characterize the material due to its simplicity and high sensitivity in measuring the third-order optical nonlinearity. This allows computing the contributions of nonlinear absorption and nonlinear refraction towards nonlinearity. The characterization of the sample was also done using the FT-IR for percentage of transmission of the C60 molecule and it was found that the sample showed highest transmission (reference is 4000 cm-1 at 100%), (97.8%) at 450 cm-1 (0.002222 cm wavelength) and the lowest transmission percentage (5%) at 1426 cm-1 (0.00070126 cm wavelength), indicating that at the lower wavelength, the sample has low percentage of transmittance and at higher wavelength it has high percentage of transmittance. It is seen from the experimentally recorded data above, that the contributions of nonlinear absorption (β) and nonlinear refraction (n2) towards nonlinearity is established. The laser intensity dependent refractive index in the third order, namely, (χ3) has been prominent, showing negative signs for the absorptive nonlinearities. The non-linear refractive index property of C60 nano particles is thus suitable to act as an optical limiter, plasmon waveguide, sensor protection, medicine, and nano probes.

Acknowledgement

The authors wish to acknowledge with thanks, Dr.Vinitha, Assoc. Professor, Department of Physics, VIT, Chennai, India for doing the Z-scan experimental part at their laboratory, Dr. Vijayaraghavan, Asst. Professor, Department of Physics, Crescent Engineering College, Chennai, India for checking the second order NLO property for C60, DST, Govt. of India for carrying out FT-IR studies at the SAIF-IITM, Chennai, India and also would like to thank the Principal and the management of Sri Sairam Engineering College for encouraging us to present such type of work in international conferences.

References

Citation: Subramaniam TK, Vinitha G, Jayakumar CV, Premanand R (2018) Non- Linear Optical Properties of Nano Particle C60 Fullerene Using Lasers. J Laser Opt Photonics 5: 182. DOI: 10.4172/2469-410X.1000182

Copyright: © 2018 Subramaniam TK, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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