We describe the design, fabrication, and testing of a spectroscopic refractometer that employs plasmonic interferometry to measure the optical dielectric functions of materials in the visible range. The proposed device, dubbed a plasmonic refractometer, consists of an array of slit-groove plasmonic interferometers etched in a 300 nm-thick metal film (silver or gold) with arm lengths varying in ...

This study presents a laser diffractometric refractometer for measuring the refractive index of liquids. The refractive index is determined by rotating a reflection grating that is immersed in the fluid under test, and measuring the first-order Littrow diffraction angle. The Littrow angle is easily detected form the interferogram formed by the diffracted beam from the grating and the reflected ...

Methods: A total of 748 students (748 eyes) from the primary school group (PS: 483 eyes), middle school group (MS: 78 eyes) and senior high school group (SHS: 187 eyes) were included in this prospective observational case series study. The refractive error values were determined using an automatic refractometer. The spherical refractive error, cylinder power and axis were measured by non-cyclop...

Fructan was precipitated from a water and ethanol extract of oat (Avena sativa L.) and barley (Hordeum vulgare L.). The degree of polymerization and response on a differential refractometer, based on peak area and height, was compared to fructan collected from a lead-based HPLC column and to commercially available inulin. Statistically significant differences are discussed.

A total internal reflection-based differencial refractometer, capable of measuring the real and imaginary parts of the complex refractive index in real time, is presented. The device takes advantage of the phase difference acquired by s- and p-polarized light to generate an easily detectable minimum at the reflected profile. The method allows to sensitively measuring transparent and turbid liqu...

In 1968 I prepared and started my thesis study on “Prematurity and the Eye” [1]. A Danish cohort of prematures born between 1959 and 1961 were examined around the age of 10 years and compared with full-term controls. The aim of the study was to assess the ophthalmic cost of prematurity. The preliminary focus was inter alia on refraction and refractive parameters, and my advisors emphasized no l...

We present highly sensitive refractometers based on a long-period grating in a large-mode-area photonic crystal fiber (PCF). The maximum sensitivity is 1500 nm/refractive index unit at a refractive index of 1.33, to our knowledge the highest reported for any fiber grating. The minimal detectable index change is 2 x 10(-5). The high sensitivity is obtained by infiltrating the sample into the hol...

Measurement of the eye's wave aberrations has become fairly standard in recent years. However, most studies have not taken into account the possible influence of the polarization state of light on the wave aberration measurements. The birefringence properties of the eye's optical components, in particular corneal birefringence, can be expected to have an effect on the wave aberration estimates ...