Contents lists available at ScienceDirect Optics & Laser Technology journal homepage: www.elsevier.com/locate/optlastec Full length article Nonlinear optical investigations of Quinine and Quinotoxine salts by Z-scan technique M.D. Zidan a, ⁎ , A. Arfan b , A. Allahham a a Department of Physics, Atomic Energy Commission, P. O. Box 6091, Damascus, Syria b Department of Chemistry, Atomic Energy Commission, P. O. Box 6091, Damascus, Syria ARTICLE INFO PACS Number: 42.65 Ky 42.70.Nq 42.70jk 84.30Qi Keywords: Nonlinear materials Quinotoxine Z-scan technique ABSTRACT Z-scan technique was used to investigate the nonlinear optical properties of Quinine and 1-(carboxymethyl)-6- methoxy-4-(3-(3-vinylpiperidin-4-yl) propanoyl) quinolin-1-ium chloride (Quinotoxine) salts. The two salts were characterized using UV–visible, FTIR and NMR measurements. The characterization spectra confirm the expected molecular structure of the prepared “Quinotoxine “ salt. The z-scan measurements were performed with a CW Diode laser at 635 nm wavelength and 26 mW power. The nonlinear absorption coefficient (β), nonlinear refractive index (n 2 ), the ground-state absorption cross sections (σ g ), the excited-state absorption cross sections (σ ex ) and thermo-optic coefficient of the samples were determined. Our results reveal that the σ ex is higher than the σ g indicating that the reverse saturable absorption (RSA) is the dominating mechanism for the observed absorption nonlinearities. The results suggest that this material should be considered as a promising candidate for future optical devices applications. 1. Introduction The nonlinear optical properties of organic materials have attracted much attention in the past decades due to their potential applications in the development of photonic and optical devices, such as human eyes and optical sensors protection from high power laser pulses [1–4]. It is well known that the organic molecules with high π–electron delocaliza- tion can exhibit large nonlinear effects; arise from the interaction between light and electrons within individual molecular units, giving greater and faster nonlinear optical responses. The ionic organic compounds have several advantages such as: large nonlinear absorption hyperpolarizability, crystal structure controllability, high melting point and hardness when compared with the organic non-ionic compounds. These advantages have motivated many researchers to carry on more investigations related to the ionic organic materials [5,6]. Nonlinear optical properties of different organic materials have been characterized by z-scan technique, including: chalcones and their derivatives [7], and fullerenes [8,9], carbon nanotubes [10], organo- tellurium compounds [11], oxazol compounds [12] and red BS dye [13]. The single beam z-scan technique introduced by Sheik-Bahae et al. [14,15] is the simplest method to measure both the nonlinear absorption coefficient (NLA) and the nonlinear refractive index (NLR). This method is considered to be sensitive to all nonlinear optical mechanisms that give rise to a change of the refractive index and absorption coefficient. The present article reports on the use of z-scan technique at 635 nm to measure the 3rd nonlinear optical properties of Quinine and Quinotoxine (as a new salt) in ethanol. To our knowledge, there is no report of an investigation of the z-scan measurements of Quinine and Quinotoxine. 2. Experimental techniques 2.1. Materials and methods All reactions and manipulations were carried out in air with reagent grade solvents. Quinine was purchased from FLUKA, Chloroacetic acid was purchased from MERCK and used as received. IR spectra were recorded on a Jasco FT-IR 300E instrument using the KBr method and the DTGS detector, at a resolution of 4 cm -1 and a total of 64 scans in the wave number range from 400 to 4000 cm -1 . A background spectrum was subtracted in each collection. 1 H and 13 C{ 1 H} NMR spectra were recorded on a Bruker Bio spin 400 spectrometer a solution of 2% (w/v) was prepared in D 2 O. The Ultra-Violet-Visible (UV–Vis) absorption spectrum was recorded in the wavelength range 190–1100 nm using UV–vis1601 PC Shimadzu Spectrophotometer. For the synthesis of 1-(carboxymethyl)-6-methoxy-4- (3-(3-vinylpiperidin-4-yl)propanoyl)quinolin-1-ium chloride http://dx.doi.org/10.1016/j.optlastec.2016.10.004 Received 31 July 2016; Received in revised form 20 September 2016; Accepted 12 October 2016 ⁎ Corresponding author. E-mail address: PScientific8@aec.org.sy (M.D. Zidan). Optics & Laser Technology 89 (2017) 137–142 0030-3992/ © 2016 Elsevier Ltd. All rights reserved. crossmark