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Techniques of Measurements of Linear and Nonlinear Optical Properties of Layered Nanomaterials for Applications in Photonics
Published in Tarun Kumar Gangopadhyay, Pathik Kumbhakar, Mrinal Kanti Mandal, Photonics and Fiber Optics, 2019
Pathik Kumbhakar, S. Biswas, A. K. Kole
The single beam Z–scan technique was developed by Sheik-Bahae et al. in 1989 [100]. Due its simple experimental arrangement, Z–scan technique has become the effective tool for determining the nonlinear optical properties of a wide variety of nonlinear materials. In this method, the sample is translated in the Z–direction along the axis of a focused Gaussian beam, and the far field intensity is measured as a function of sample position. This technique not only helps us to measure the magnitude of both real and imaginary part of the third and higher order nonlinear susceptibility coefficient, but also the sign of the nonlinearity of materials [101]. In the Z–scan technique, the light matter interaction is exploited in which an incident beam propagating inside a nonlinear medium induces a self-phase change thereby producing a wave front distortion of the beam. A laser beam propagating through a nonlinear medium will experience both amplitude and phase variations. Thus, if we measure the transmission of a focused laser beam through the sample as a function of distance from the sample, we will get information about nonlinear absorption (NLA) and nonlinear refraction (NLR) due to amplitude and phase variations, respectively. Some other advantages of Z–scan technique are data analysis is quick and simple except for some particular conditions, close similarity between the geometries of Z–scan, and the optical power limiting techniques. Like all other techniques it has some disadvantages as well. The main disadvantages of the Z–scan technique are stringent requirement of high quality Gaussian TEM00 beam for absolute determination of the nonlinearities from the experimental data and for non–Gaussian beams the analysis is completely different, relative measurements against a standard samples allow relaxation on requirements of beam shape [100,102].
Measurement Techniques for Third-Order Optical Nonlinearities
Published in Hari Singh Nalwa, Seizo Miyata, Nonlinear Optics of Organic Molecules and Polymers, 2020
10.6 ?m is shown in Figure 15. The negative (self-defocusing) optical nonlinearity is indicated by the Z-scan peak-to-valley configuration. The Z-scan of a 2.5 mm thick BaF2 single crystal using a 27 ps pulse at 532 nm is shown in Figure 16. In this case, a positive (self-defocusing) optical nonlinearity can be observed. The Z-scan technique has been used to determine the optical nonlinearities of solutions and thin films.
(3) Processes
Published in Peter E. Powers, Joseph W. Haus, Fundamentals of Nonlinear Optics, 2017
Peter E. Powers, Joseph W. Haus
In addition to measuring the nonlinear index, the z-scan technique can also measure nonlinear absorption. By removing the pinhole and measuring the total power as a function of sample position z, the z-scan technique provides a measure of changes in the integrated power hitting the detector.
Investigations on synthesis, growth and physicochemical properties of organic nonlinear optical crystal: 2-aminopyridinium maleate
Published in Inorganic and Nano-Metal Chemistry, 2023
E. Raju, P. Jayaprakash, R. Ravisankar, M. Lydia Caroline, G. Vinitha, S. Kumaresan
To discover the third-order optical nonlinearity of materials, many opticians utilize the Z-scan technique.[20] Substituting for the Z-scan approach, the NLO crystal third-order nonlinear optical susceptibility χ(3) and nonlinear absorption coefficient (β) are used in order to get the intensity-dependent nonlinear refractive index (n2). The Z-scan experiment was executed by a diode pumped Nd: YAG laser with a 532 nm wavelength as a source. Figure 8 (a) and (b) present the closed and open aperture curves, displaying the recorded normalized transmittance for 2APM crystal in observing the values of the Z-position. Nonlinear absorption and nonlinear refractive index are precisely proportional to the imaginary and real parts of susceptibility.[21] The closed aperture implies that the 2APM crystal is self-defocusing, because its refractive index, n2, is negative. The nonlinear absorption coefficient in the 2APM crystal (β) is shown in open aperture (maximum transmittance).
Z-scan analytical expressions for weak thick nonlocal nonlinear media
Published in Journal of Modern Optics, 2020
R. Torres Romero, M. M. Méndez Otero, M. L. Arroyo Carrasco, B. A. Martínez Irivas, M. D. Iturbe Castillo
Media which respond to excitation on not only the excitation point but also on within its nonlocal or immediate vicinity are important in nonlinear optics. Z-scan is a widely used technique for the characterization of nonlinear media, however, z-scans of thick nonlocal nonlinear media has received little attention. The z-scan technique [1], was proposed to evaluate the sign and magnitude of the nonlinear refractive index of third-order nonlinear materials. The transmittance of a sample, illuminated by a focused laser beam, is measured from far field as a function of the sample position. Close or open detection gives information on the nonlinear refractive or absorptive index. Initially, the technique was proposed for thin Kerr samples under Gaussian beam illumination and on-axis intensity detection and small nonlinear phase shifts [2,3]. Recently the nonlocal, nonlinear response of thin samples has been considered in the z-scan technique [4].
Light control through a nonlinear lensing effect in a colloid of biosynthesized gold nanoparticles
Published in Journal of Modern Optics, 2019
A. Balbuena Ortega, E. C. Brambila, V. López Gayou, R. Delgado Macuil, A. Orduña Diaz, A. Zamilpa Alvarez, A. V. Arzola, K. Volke-Sepúlveda
In this work, we report a thorough experimental investigation of the nonlinear optical properties of four samples of gold nanoparticles synthesized using hydroalcoholic extract and three different compounds of the plant Bacopa procumbens. The obtained samples are characterized by UV-Vis and transmission electron microscopy (TEM). The different compounds of the plant extract are selected in order to modify the size of the nanoparticles, resulting in samples with mean particle diameters between 3 and 5 nm. The Z-scan technique is used for analysing the behaviour of the nonlinear refractive index and the nonlinear absorption. As we use a wavelength sufficiently close to the plasmon resonance and the particles are small enough to neglect the optical forces, the thermal effects are predominant. Finally, we investigate the application of these nanocolloids for the generation of self-collimated beams (SCBs) and their use to controlling a weaker probe beam of a different wavelength. In contrast with previous works, reporting bright soliton formation with powers from hundreds of mW up to some watts in a CW laser (18) or pulses with a very high peak power, of the order of 105 W (19), we will show that the mechanism of formation of the SCBs here is rather a negative-lens effect, which shifts forward the focal position of a convergent input beam.