Development of High Accurate Family-use Digital Refractometer Based on CMOS

This study aims to develop a low-cost refractometer for measuring the sucrose content of fruit juice,which is an important factor affecting human health.While laboratory-grade refractometers are expensive and unsuitable for personal use,existing low-cost commercial options lack stability and accuracy.To address this gap,we propose a refractometer that replaces the expensive CCD sensor and light source with a conventional LED and a reasonably priced CMOS sensor.By analyzing the output waveform pattern of the CMOS sensor,we achieve high precision with a personal-use-appropriate accuracy of 0.1%.We tested the proposed refractometer by conducting 100 repeated measurements on various fruit juice samples,and the results demonstrate its reliability and consistency.Running on a 48 MHz ARM processor,the algorithm can acquire data within 0.2 seconds.Our low-cost refractometer is suitable for personal health management and small-scale production,providing an affordable and reliable method for measuring sucrose concentration in fruit juice.It improves upon the existing low-cost options by offering better stability and accuracy.This accessible tool has potential applications in optimizing the sucrose content of fruit juice for better health and quality control.

Monitoring Passive Transfer of Immunity in Neonatal Calves by Measuring Levels of IgG in Blood Using Immunoassay Method and Refractometer Measures of Serum and Colostrum

IgG Check calf test has been used in this study to identify if a failure of passive transfer occurs in neonatal calves by measuring the level of IgG in blood. An adequate level of IgG measured in all calves at 48 hours, 7 days and 14 days after birth showed level of IgG 1000 mg/dl. This level indicated that they have good passive transfer of immunity. Also, in this study colostrum quality fed to calves was detected using Brix Refractometer. The colostrum is of high quality as it contains 50 mg/ml of IgG. This Brix refractometer can be used on the farm level to estimate colostrum IgG content and monitoring colostrum feeding practices. Colostrum with high quality IgG could provide calves with enough IgG to attain successful passive transfer of immunity. Brix and Obione refractometers provide simple, rapid method for estimating IgG concentration on calf serum, thus considered to be the most common method for determining passive transfer failure.

Pascal Realization by Comb-Spectral-Interferometry Based Refractometer

To break through the limitations of existing pressure standards, which rely on the gravity and toxic mercury,the national metrological institutes prefer a quantum-based pressure standard. Combining the ideal gas law with helium refractivity measurement, we demonstrate a scheme for the realization of the pressure unit. The refractometer is based on a spectral interferometry with an optical frequency comb and a double-spaced vacuum cell. Through fast Fourier transform of the spectral interferograms of the two beams propagating inside and outside the vacuum cell, the helium refractivity can be obtained with a combined standard uncertainty u（n） of2.9 × 10-9. Moreover, the final u（n） is -8.7 × 10-6 in a measurement range of several megapascals（MPa）. Our apparatus is compact, fast（15 ms for one single measurement） and easy to handle. Furthermore, the measurement uncertainty will be improved to-1 × 10-9 or lower if a VIPA-based spectrometer is used. The value of u（p） will thus increase to 3 × 10-6 or better in several MPa.

Validation of the Methods for Detection the Non-Milk Fat in a Mixture of Milk Fat and Palm Oil

Milk fat contains a variety of nutritive and health-promoting compounds that guard against some disease. In the current system of global competition, when the quality of milk and milk products is not an option but rather a requirement, therefore, determining the purity of milk fat is critical. This study aims to validate analytical methods for detecting palm oil in a mixture of milk fat and palm oil. Methods of this study was involved detection of non-milk fat in fat blinders by determining the saponification value, iodine number, refractive index, butyro refractometer reading, Gas chromatography, Reverse Phase High-performance liquid chromatography, and Fourier transforms Infrared. The results of this study revealed that the saponification value, Iodine number, refractive index, and Butyro Reading could be used to detect the addition of palm oil by a level of 10% - 20% or more to the milk. The level of some fatty acids in the milk as determined by GC, such as myristic acid (C14:0), palmitic acid (C16:0), and stearic acid (C18:0), is correlated well with the level of adding palm oil to milk fat. The determination of cholesterol and β-sito-sterol content by RP-HPLC could be used for the detection of the addition of palm oil to milk fat. The spectrum behavior produced by FTIR spectroscopy in this adulterated sample is almost the same, so this technique could not be used to detect the palm oil in milk fat.

Comparison of Sugar Content in Bottled 100% Fruit Juice versus Extracted Juice of Fresh Fruit

This paper presents findings of an experiment for the comparison of sugar concentration in extracted juice of fresh fruit to that of commercially-bottled 100% fruit juice with a “no sugar added” attribute. The goal of the study was to determine if the sugar content of bottled 100% fruit juice with a “no sugar added” label is equivalent to that of extracted juices of fresh fruits. The reported study was performed to address the potential concern that commercially-bottled 100% fruit juices with “no sugar added” may contain higher sugar content than extracted juice of fresh fruit. The fruit juices that were tested included apple, grapefruit, orange, pineapple, pomegranate, red grape and white grape. All bottled juices and fresh fruits were purchased in Toledo, Ohio, USA during the winter of 2012. The fresh fruits were juiced and three samples were tested for sugar concentration using a Brix refractometer. The same testing protocol was also applied to the bottled 100% fruit juice. Application of the Mann-Whitney test on the experimental data demonstrated no statistically significant difference (p > 0.05). The results suggested that the sugar content in the commercially bottled 100% fruit juice with the “no sugar added” label is an accurate representation of sugar content in the freshly-extracted juice of the corresponding fruit.

Refractive index sensor based on tapered PCF in-line interferometer

A simple and compact refractive index sensor is demonstrated by tapering a photonic crystal fiber （PCF） in-line interferometer. The PCF is spliced between two single-mode fibers and tapered via hydrofluoric acid etching. Its sensitivity in liquid is more than an order of magnitude larger than the untapered one. By optimizing the etching process, we can fabricate more uniformly and thinly tapered PCF interferometers with higher sensitivity in the future.

Influences of Y_2O_3 dopant content on residual stress,structure,and optical properties of ZrO_2 thin films

Four kinds of Y2O3 stabilized ZrO2 （YSZ） thin films with different Y2O3 contents （from 0 to 12 mol%） are deposited on BK7 glass substrates by electron-beam evaporation method. The effects of different Y2O3 dopant contents on residual stress, structure, and optical properties of ZrO2 thin films are investigated. The results show that residual stress in YSZ thin films varies from tensile to compressive with the increase of Y2O3 molar content. The addition of Y2O3 is beneficial to the crystallization of YSZ thin film and transformation from amorphous to high temperature phase, and the refractive index decreases with the increase of Y2O3 molar content. Moreover, the variations of residual stress and the shifts of refractive index correspond to the evolution of structures induced by the addition of Y2O3.

Highly sensitive and wide-dynamic-range liquid-prism surface plasmon resonance refractive index sensor based on the phase and angular interrogations

In this study, a new method utilizing surface plasmon resonance （SPR） sensing technology based on the phase and angular interrogations for measuring the refractive index of a liquid prism is presented. An orthogonal sam- ple box that combined the functions of a prism, cell box, and mirror is adopted to simplify the system and provide the convenience to implement the phase and angular interrogations. The angular interrogation is achieved by the motorized rotation stage with the new sample box, and the phase interrogation is achieved by the linear polari- zation interferometry between the s- and p-polarization components. The amplitude reflectivity and the phase angle, which are the functions of the incident angle, are obtained by the reflection intensity and the interference intensity of the lights directly. A sensitivity of 7.5 × 10^-7 refractive index unit （RIU）/0.1° and a dynamic range of 0.5 RIU are obtained experimentally and theoretically.

Negative refractive index in non-resonance spectrum area

A new concept to realize negative refractive index in non-resonance spectrum using chiral metamaterial is proposed.A low-index metamaterial is added to diminish the effective refractive index of the combined structure.Simulation and material parameter retrieval procedures are carried out to determine material performances.Results show evidence of negative refractive index and strong optical activity in the new chiral metamaterial.

Investigation of mode radiation loss for microdisk resonators with pedestals by FDTD technique

Mode radiation loss for microdisk resonators with pedestals is investigated by three-dimensional（3D） finite-difference time-domain（FDTD） technique.For the microdisk with a radius of 1μm,a thickness of 0.2μm,and a refractive index of 3.4,on a pedestal with a refractive index of 3.17,the mode quality（Q） factor of the whispering-gallery mode（WGM） quasi-TE_（7.1） first increases with the increase of the radius of the pedestal,and then quickly decreases as the radius is larger than 0.75μm.The mode radiation loss is mainly the vertical radiation loss induced by the mode coupling between the WGM and vertical radiation mode in the pedestal,instead of the scattering loss around the perimeter of the round pedestal.The WG M can keep the high Q factor when the mode coupling is forbidden.

Effect of crystalline lens surfaces and refractive index on image quality by model simulation analysis

The surfaces and refractive index of crystalline lens play an important role in the optical performance of human eye. On the basis of two eye models, which are widely applied at present, the effect of lens surfaces and its refractive index distribution on optical imaging is analyzed with the optical design software ZEMAX （Zemax Development Co., San Diego, USA）. The result shows that good image quality can be provided by the aspheric lens surfaces or （and） the gradient-index （GRIN） distribution. It has great potential in the design of intraocular lens （IOL）. The eye models with an intraocular implantation are presented.

Simultaneous temperature and refractive index measurement of liquid using a local micro-structured fiber Bragg grating

An alternative solution for the simultaneous measurement of temperature and refractive index is presented. A local micro-structured fiber Bragg grating （LMSFBG） is formed as the sensing head, in which a standard grating is etched by HF. According to the phase shift theory, the main spectral change of the LMSFBG is the formation of a narrow allowed band, which is strongly dependent on the etching features and the surrounding refractive index. As such, the temperature and refractive index measurements can be achieved by the shifts of the double peaks and narrow allowed band, and their fitting linearity coefficients are 0.996 and 0.994, respectively. Thus, the reflection and transmission peaks of the LMSFBG have a good linear relationshi~ with tem^era,ture and refractive index.

Light propagation and reflection-refraction event in absorbing media

The light propagation within an absorbing medium and the reflection and refraction at the interface of two absorbing media are studied. By using the unit vectors denoting the planes of constant field amplitude and constant phase respectively, the light propagation and attenuation are described by the effective refractive indices which depend on both the complex refractive index of the medium and the angle between the unit vectors. With the expression for the light propagation, the corresponding Snell＇s law and the expression of Fresnel coefficients are obtained, which can be applied to describe the reflection-refraction event at the interface between an arbitrary combination of transparent and absorbing media.

A method of measuring the refractive index of extraordinary ray in uniaxial crystal with optic axis at an arbitrary orientation

A new equation to measure the refractive index of extraordinary ray in uniaxial crystal with the optic axis at an arbitrary orientation has been given in this letter, and the term in this equation makes the measurements to be relatively easy. The theoretical study shows that the accuracy achieved in the experiments attains to the order of magnitude in 10^-3. .

Light transmission in porous silicon dioxide filled with liquids of different refractive indices

Optical transmission at 532 nm from nonabsorbing disordered porous silicon dioxide has been studied experimentally. The transmission behaviors can be adjusted by filling the pores with liquids of different refractive indics, which are analyzed based on the theory of diffusion in a weak scattering regime. In our experiment, the transmission coefficient changes from a value less than 1% to one that is greater than 75%, that is, the opaque sample becomes transparent, which means that the transport mean free path of light within the material has been effectively adjusted. In addition, this method is a useful nondestructive method to derive the refractive index of an unknown bulk porous material.

Liquid refractive index sensor based on polymer fiber with micro-holes created by femtosecond laser

We present a liquid refractive index （RI） sensor based on step-index multimode polymer optical fiber with a micro-hole drilled by the femtosecond laser. The experimental results show that in the RI operation range of 1.333-1.473, the sensor has a good linear loss （dB） response to the liquid RI in the micro-holes and a high sensitivity of 18 dB/RIU approximately. The experimental results are explained with the mode of the refrac- tion loss caused by the hole core interface and connection loss caused by the gap of the holes. The sensor has many advantages including high sensitivity and low cost.

Optical humidity-sensitive mechanism based on refractive index variation

A novel composite model is put forward for humidity-sensitive material based on Maxwell-Garnett and effective medium theory. The analytical expression of the relation between effective refractive index and relative humidity is shown with different absorption factors and porosities. The larger the absorption factor is, the higher the refractive index is. The refractive index of humidity-sensitive SiO2 film decreases with the increase of ceramic material porosity. The sensitivity of optical humidity sensor can reach the magnitude of 10-3. In comparison with the experimental humidity-sensing curve by the method of p-polarized reflectance and the analysis of mechanism, theoretical simulation is in agreement with experimental results. Therefore, this composite model is proved to be reasonable which lays new theoretical foundation in further research on optical humidity sensor.

Reflex optical sensor based on dual metal gratings with high angular sensitivity

An interesting reflection phenomenon in a dual metal grating （DMG） structure is studied, which is related to the competition between Fabry-Prot （F-P） resonance effect and evanescent-field coupling effect inside the gap between the two composing single metal gratings. This competition leads to high angular sensitivity in response to the refractive index variation of the sample solution in the gap. A reflex optical sensor with high sensitivity based on DMG for detecting the change in refractive index is proposed and its performance theoretically is discussed.

Fourier analysis of elastic light scattering spectrum of epithelial cell nuclei

A new method for simultaneously determining the size and refractive index of epithelial cell nuclei is presented. The function of the modified elastic light scattering spectrum is regarded as a function of wave number factor, Q=2λ-1sin（θ/2）. The modified spectrum has a constant oscillation period with its frequency proportional to the average diameter of cell nuclei. To the same average diameter, the different relative refractive indexes of epithelial cell nuclei only induce the horizontal shift of the spectra. Both the oscillation frequency and the horizontal shift are quantified by the fast Fourier transform on the modified spectra. The average diameter can be figured out through the peak frequency divided by the value of the refractive index of the surrounding medium. The phase angle of the peak frequency has an approximate linear relationship with the relative refractive index of epithelial cell nuclei.

Guided modes in the chiral negative refractive index fiber

The novel characteristics of guided modes in the chiral negative refractive index fiber are investigated theoretically in this letter.We derive the characteristic equation of guided modes.Based on two types of chiral metamaterial parameters,we present the dispersion curves,energy flux,and power of guided modes.Some abnormal features,such as the existence of surface mode and dispersion curves with different shapes,intersection of dispersion curves of different guided modes,negative energy flux in the achiral cladding,and zero power at some normalized frequencies,are found in the chiral negative refractive index fiber.