Automatic VIS- near IR laser refractometer

Abstract

This work presents a simple automatic VIS-IR laser refractometer, based on a critical-angle method. Its experimental error is smaller than 6×10−4 within the range of 1.32–1.47. Such precision of the refractometer is sufficient for the most industrial applications, for environmental protection, structural analysis, investigation of new materials, etc. Spectral refractive index measurements of different liquids are led and the calculated dispersion coefficients are reported.

Planar near-infrared surface plasmon resonance sensor with Si prism and grating coupler

“…1a) in the condition that the wavelength of incident light was 1550 nm. The refractive indices used in this calculation are 3.52 for Si [18], 0.57 + 9.66i for Au [19], 1.31 for water [20], 1.35 for ethanol [21], and 1.00 for air. The angle  at which light can be incident is determined by prism's slope angle (54.74 • ) and the refractive indices of the prism material (Si) and material in contact with the prism at the incident surface.…”

Dispersion and refractive index measurements of diluted solutions with a double prism refractometer

“…The analytical calibration was made with sucrose solutions since its specific refractive index increment is reported (dn/dc= 0,145 ml/g for 633 nm) in literature [1]. In Fig.…”

“…For a monochromatic beam and under isothermal conditions, the change in the refractive index of the solution in prism 2 due to a change in concentration is given by [1]:…”

“…The system allows to estimate changes of the refractive index by using the refraction of a white light beam by a double prism refractometer containing the medium to be characterized. The light is finally analyzed with a spectrophotometer integrated to an automated system, which allows faster measurements and is simpler than already proposed by Sarov [1], Rheims [2] and Cooper [3].…”

Refractive index measurement using laser diffractometer

“…In addition to research in pitch measurements, using laser diffractometer or interferometer to measure the liquid's refractive index is also a breakthrough [6,9,13]. There were many methods for refractive index measurements early, such as Sarov et al, using their refractometers by Abbe number and critical-angle [11]. Castrejón-Pita used the total internal reflection to conduct their refractive index measurement [1].…”