Refractive Index Of Optical Glass Research Articles

Effect of macroscopic defects on optical properties of fluorophosphate glasses

Fluorophosphate glass is the core of laser materials and also has an important reference value for an optical lens. According to Kirchhoff’s law, this paper focuses on the optical loss of incident light entering fluorophosphate glass. The transmittance and refractive index of optical glass were measured by an ultraviolet-visible spectrophotometer (Uv) and V-prism tester. With the sample thickness increasing from 10 mm to 50 mm, the transmittance of grade 4 fluorophosphate glass decreases from 85.32 % to 76.91 %, and the scattering rate increases from 8.4704 % to 17.0591 %. The microstructure and internal images of macroscopic defects were obtained by projective optical microscopy. In addition, an electron probe (EPMA) was used to analyze the defective components and identify the main components of the defects. The results show that the high content of P/Al/O element is the main cause of optical loss.

Prism-pair interferometer for precise measurement of the refractive index of optical glass by using a spectrum lamp.

A prism-pair interferometer for a spectrum lamp was developed for precise measurement of the refractive index of a prism of optical glass. Previously we reported the prism-pair interferometer with a He-Ne laser light source, resulting in a measurement uncertainty of 1.1×10⁻⁶. However, most of the refractive-index values managed by optical glass manufacturers are conventionally measured with spectrum lamps. We have optimized the prism-pair interferometer for spectrum lamps and implemented a signal-processing technique from Fourier-transform spectroscopy. When the refractive index is measured, the wavelength of the spectrum lamp is simultaneously calibrated by part of the interferometer, so that the resulting refractive index is traceable to a national standard of length. The combined standard uncertainty for a refractive index measured with the e-line (546 nm) of a Hg lamp is 6.9×10⁻⁶.

Study on Measuring System of Automatic Image Alignment Refractive Index Based on New Mathematical Model

With the development of measuring technology,the measuring accuracy of optical glass refractive index of the increasingly high demand,V prism refractometers is major general instrument for measuring the refractive index of optical glass,not only the simple device,convenient measurement,and this method has high precision performance,however,the accuracy is only attained ,which in the regulation of national metrology verification and the introduction of V prism refractometers in the literature,the classic formula calculation principle formula error caused by refractive index has more than .Based on the mechanical structure and optical transmission to improve the original V prism refractometers the refractive index of air,by considering the influence on measurement precision of V prism refractometer,to mathematical modeling of V prism refractometer the principle formula,V can be measured refractive prism refractometer rate accuracy increased to ,measurement repeatability less than ,has important practical significance for realizing high accuracy measurement of the refractive index of optical glass.

Finite Element Calculation of Refractive Index in Optical Glass Undergoing Viscous Relaxation and Analysis of the Effects of Cooling Rate and Material Properties

In this research, a methodology based on a numerical simulation model is presented to predict refractive index change introduced to two low Tg optical glasses, namely, P‐SK57 and P‐LASF47, by cooling. To model the structural relaxation behavior of glass around glass transition temperature, the Tool–Narayanaswamy–Moynihan (TNM) model is used. In addition, the fictive temperature of the glass samples during cooling is discussed. The effect of cooling rate on the fictive temperature of the glass samples is also presented. This study demonstrated that finite element method is capable of predicting refractive index of optical glass undergoing viscous relaxation. The simulated results in this study confirm that a higher cooling rate leads to a lower refractive index and a larger variation of refractive index in glass optics. The results also suggest that for glass, materials with high thermal conductivity and low heat capacity are preferred for compression molding process.

Prism-pair interferometry by homodyne interferometers with a common light source for high-accuracy measurement of the absolute refractive index of glasses

A prism-pair interferometer comprising two homodyne interferometers with a common light source was developed for high-precision measurements of the refractive index of optical glasses with an uncertainty of the order of 10(-6). The two interferometers measure changes in the optical path length in the glass sample and in air, respectively. Uncertainties in the absolute wavelength of the common light source are cancelled out by calculating a ratio between the results from the interferometers. Uncertainties in phase measurement are suppressed by a quadrature detection system. The combined standard uncertainty of the developed system is evaluated as 1.1×10(-6).

High-accuracy interferometer with a prism pair for measurement of the absolute refractive index of glass

We propose a variable-path interferometric technique for the measurement of the absolute refractive index of optical glasses. We use two interferometers to decide the ratio between changes in the optical path in a prism-shaped sample glass and in air resulting from displacement of the sample. The method allows precise measurements to be made without prior knowledge of the properties of the sample. The combined standard uncertainty of the proposed method is 1.6x10(-6).

The effects of thermal treatment below the glass transition temperature on the refractive index of optical glass

It is well known that the refractive index of glass depends on the annealing process starting at temperatures above the glass transition temperature T g. However, the refractive index can also be changed by heat treatment far below T g. These effects of heat treatment are important since they can occur during the finishing process of optical glasses, e.g., cementing, polishing and coating. We have investigated the refractive index of optical glasses before and after heat treatment at temperatures 100 K or more below T g, followed by fast cooling to room temperature. We observed changes of the refractive index as large as 2 × 10 −4 depending on the type of glass. An overview will be given on the behaviour of different glass types.

Influence of Oscillator Strength on the Refractive Index of Optical Glasses

Influence of Oscillator Strength on the Refractive Index of Optical Glasses

A Special Method for Precise Refractive Index Measurement of Uniaxial Optical Media

A method was developed for measuring the refractive index of optical glasses and uniaxial crystalline solids when established refractometric methods are not feasible. A synthetic ruby cuboid was contacted to a prism of known refractive index and a spectrometer was used to measure the angles describing the optical path through the ruby-glass combination. Ray tracing equations were derived to compute the refractive index accurate within 3 x 10(-5). Index values for both polarizations of ruby are given at selected wavelengths from 0.4358 microm to 0.7065 microm.