Optical Properties of Sodium Chloride Solution within the Spectral Range from 300 to 2500 nm at Room Temperature

Abstract

The optical properties of sodium chloride (NaCI) solution were experimentally determined by double optical pathlength transmission method in the spectral range from 300 to 2500 nm at the NaCl concentration range from 0 to 360 g/L. The results show that the refractive index of NaCl solution increases with NaCl concentrations and correlates nonlinearly with the concentration of NaCl solution. The absorption index of NaCl solution increases with NaCl concentrations in the visible spectral range of 300-700 nm, but varies little in the near-infrared spectral range of 700-2500 nm at room temperature. For the sake of applications, the fitted formulae of the refractive index and absorption index of NaCl solution as a function of wavelength and NaCl concentration are presented.

Tapered photonic crystal fibers coated with ultra-thin films for highly sensitive bio-chemical sensing

“…A special work cell was designed with a working volume of 50 μl and a cavity length of 13 mm to measure small volumes of investigated solutions with our fiber sensor. Before biosensor experiments, we tested a sensitivity of our device for bio-sensing RI range using a sodium chloride (NaCl) diluted in a distilled water in the following concentrations, 0.0, 0.2, 0.4, 0.6, 0.8, and 1 M. Calculated refractive indices of investigated solutions at 1550 are, respectively, 1.30864, 1.31104, 1.31339, 1.31569, 1.31794, and 1.32014 [8]. Figure 2(a) shows that transmission peaks shift to longer wavelength as the refractive indices of the NaCl solutions increase.…”

Modal Interferometers Based on a Tapered Special Photonic Crystal Fiber for Highly Sensitive Detection

“…The cell was fabricated with a working volume of 50 μl and a cavity length of 13 mm. To test a sensitivity of our device for biosensing RI range, solutions of sodium chloride (NaCl) diluted in distilled water were prepared in the following concentrations, 0.0, 0.2, 0.4, 0.6, 0.8, and 1 M, with corresponding refractive indices at 1550 nm of 1.30864, 1.31104, 1.31339, 1.31569, 1.31794, and 1.32014 [59]. An antigen-antibody test was proposed to evaluate the performance of the device for a biosensor application.…”

Comparison between transmittance equations of optical cell for calculating optical constants of liquid materials

“…However, transmittance of liquid materials attained by the equivalent method or effective method are not same with the absolute transmittance of neat liquids. Otanicar et al [18] improved the double-thickness transmittances method proposed by Tuntomo and Tien, which iteratively calculates optical constants of liquid materials by using transmittances of optical cell filled with liquid materials at two different thicknesses, but in the transmittance calculation of optical cell filled with liquid materials the overall medium was divided into discrete elements, and in fact there is no vacuum inter-space among the three-layer system [19,20]. Li et al [19,20] proposed a novel inversion model of optical constants based on continuous absorbing layers consisting of multiple reflections that is more suitable for liquid measurement, which effectively improves the Otanicar's method.…”

“…Otanicar et al [18] improved the double-thickness transmittances method proposed by Tuntomo and Tien, which iteratively calculates optical constants of liquid materials by using transmittances of optical cell filled with liquid materials at two different thicknesses, but in the transmittance calculation of optical cell filled with liquid materials the overall medium was divided into discrete elements, and in fact there is no vacuum inter-space among the three-layer system [19,20]. Li et al [19,20] proposed a novel inversion model of optical constants based on continuous absorbing layers consisting of multiple reflections that is more suitable for liquid measurement, which effectively improves the Otanicar's method. Li et al [21] developed a novel double-thickness transmittances method to determine optical constants of liquid materials by using transmittances of optical cell filled with liquid materials at two different thicknesses based on search or intelligence arithmetic methods, which also considered continuous absorbing layers consisting of multiple reflections.…”

“…In the inversion methods of optical constants of liquid materials based on transmittance spectrum of optical cell, the equation of the total transmittance at normal incidence of optical cell filled with liquid material is a key to the calculation precision. There are three equations to calculate the total transmittance at normal incidence of optical cell filled with liquid materials, including Li's equation [19,20], Li's equation [21] and Kameya's equation [17]. The equations of Li [19][20][21] considered the multiple transmission through the glass and liquid materials, but the equation of Kameya only considered the multiple transmission through the liquid materials.…”