Design, construction, and performance of a real-time holographic refractometry prototype for liquid analysis

Abstract

The development and the performance of a portable holographic refractometer prototype for liquid measurement employing multimode diode lasers with emission centered at 662 nm as light sources is reported. Due to the multiwavelength character of the holographic recording, a synthetic wavelength was generated, and the diffracted wave intensity was thus modulated as a function of the optical path difference between the reference and the object beams. The transparent test cell containing the liquid was placed at the reference-beam arm of the optical setup, while the contour interferogram generated on the holographic image of a flat object was used for fringe counting. A change L on the liquid column length is proportional to the p running fringes on the object image, and from this relation the refractive index of the test liquid was obtained. The holograms were recorded on a photorefractive Bi 12 TiO 20 crystal whether using a single multimode diode laser or by combining two diode lasers. In the latter configuration the synthetic wavelength can be varied in order to enhance the measurement sensitivity and/or to allow the analysis of turbid liquids. The size of the whole prototype is 54 × 22 × 14 cm 3 . The refractive indexes of ethanol/water mixtures with different concentrations were measured, as well as the NaCl concentrations in aqueous solutions were determined upon comparison with an empirical curve. In both cases the results were compared with the ones obtained through an Abbe refractometer.

Realization of Enhanced Evanescent Field Long Period Fiber Grating near Turn around Point for Label-Free Immunosensing

“…SRI sensitivity analysis was performed using NaCl solutions in water (0.0-0.5% w/v) (RI in the range 1.333 to 1.3335 [25]) and the immunoassay was carried out using mouse IgG/Anti mouse IgG interaction [10]. BSA was used to block the nonspecific adsorption.…”

Прецизионная Интерферометрия Как Новый Метод Исследования Конформационного Состояния Белка И Его Взаимодействия С Растворителем

“…Помимо температурной зависимости показателя преломления воды в литературе хорошо описана зависимость показателя преломления растворов от концентрации различных веществ, в частности, для растворов NaCl [18][19][20][21][22]. В связи с этим было интересно проверить точность калибровки интерферометра, полученной по изменению температуры в воде, с помощью концентрационной зависимости показателя преломления водного раствора NaCl.…”