Refractive index measurements of poly(methyl methacrylate) (PMMA) from 04–16  μm

Beadie, G.; Brindza, Michael R.; Flynn, Richard A.; Rosenberg, A.; Shirk, James S.

doi:10.1364/ao.54.00f139

Cited by 215 publications

(100 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…However,t he transparent wood samples prepared by this method were small and of low thickness, unable to meet practical application requirements. [24] Figure 1( the image at the lower right corner) illustrates the transparent wood prepared by infiltrating PMMA into intact delignified wood, which displayed extraordinaryt ransparency in the case of at hickness of 1.5 mm or less, as previously described. The chemical treatment of natural wood caused as ignificant drop in lignin and hemicellulose content,b ut only am odest dissolution of cellulosec ontent,i ndicating that the cellulose is the mainly preserved component after treatment( Ta ble1).…”

Section: Resultsmentioning

confidence: 90%

Large‐Size Transparent Wood for Energy‐Saving Building Applications

et al. 2018

View full text Add to dashboard Cite

As an energy‐saving building material, transparent wood (TW) is highly attractive because of the advantages of high optical transmittance, excellent mechanical properties, and good thermal insulation. However, the current research is limited to fabricating small‐size samples in the laboratory because thick or large‐size transparent wood is almost impossible to be achieved. A method that can easily and efficiently produce transparent wood with any size and any thickness is desirable for practical applications. Transparent wood made from wood fibers as a substrate allows the cell walls to bind more tightly to the impregnated polymer, resulting in high light transmittance. Compared with wood prepared by using previously reported approaches, the transparent wood prepared by this new method not only retains the same advantages but also has higher preparation efficiency and is suitable for large‐scale production. Under a simulated real environment, the retainability of indoor temperature by a sample house utilizing the transparent wood reveals excellent thermal insulation of the fiber‐based transparent wood owing to its low thermal conductivity, showing significant benefits in saving thermal energy.

show abstract

Section: Resultsmentioning

confidence: 90%

Large‐Size Transparent Wood for Energy‐Saving Building Applications

et al. 2018

View full text Add to dashboard Cite

show abstract

“…If the measured fiber length change is intended to be used for humidity measurement, temperature variations of the sensor also have to be considered: besides the unknown Δ n /ΔRH dependence of PMMA, the temperature-dependent refractive index change of PMMA is negative with about −137 × 10 −6 K −1 at 20.1 °C [37]. The linear thermal expansion coefficient is in the order of 75 × 10 −6 K −1 [29] and also depends on the water content in the fiber ranging from 70.4 × 10 −6 K −1 to 92.8 × 10 −6 K −1 at 50 °C [33].…”

Section: Resultsmentioning

confidence: 99%

Distributed Humidity Sensing in PMMA Optical Fibers at 500 nm and 650 nm Wavelengths

Liehr

Breithaupt

Krebber

2017

Sensors

View full text Add to dashboard Cite

Distributed measurement of humidity is a sought-after capability for various fields of application, especially in the civil engineering and structural health monitoring sectors. This article presents a method for distributed humidity sensing along polymethyl methacrylate (PMMA) polymer optical fibers (POFs) by analyzing wavelength-dependent Rayleigh backscattering and attenuation characteristics at 500 nm and 650 nm wavelengths. Spatially resolved humidity sensing is obtained from backscatter traces of a dual-wavelength optical time domain reflectometer (OTDR). Backscatter dependence, attenuation dependence as well as the fiber length change are characterized as functions of relative humidity. Cross-sensitivity effects are discussed and quantified. The evaluation of the humidity-dependent backscatter effects at the two wavelength measurements allows for distributed and unambiguous measurement of relative humidity. The technique can be readily employed with low-cost standard polymer optical fibers and commercial OTDR devices.

show abstract

“…Unlike silicon, transparent plastics with purely real refractive indices, such as a thick acrylic bars (refractive index n ≈ 1.495), do not restrict the incident excitation at the surface, and the transmitivity is almost constant (≤ 1) throughout the range of depth of the sample used in the experiments. The two parameters R ( Z ) and T ( Z ) can be respectively written as R ( Z ) = R V [1 – U ( Z – Z 0 )] and T (Z) = T V , where R V and T V (≤ 1) are constants.…”

Section: Resultsmentioning

confidence: 99%

A model for interpreting depth profiles of confocal Raman measurements in reflective and transmitting materials

Chakraborty

Kahan

2019

J Raman Spectroscopy

View full text Add to dashboard Cite

We present a model and experimental evaluation of the depth profiles of total intensity in confocal Raman microscopy. The model assumes a Gaussian‐like beam for excitation and Raman emission to obtain a general description of the depth profile from an arbitrary sample. For samples that emit from the surface (i.e., that do not transmit light at the excitation wavelength), this model simplifies to a Lorenzian depth profile from which Rayleigh range can be extracted by the half‐width at half maxima. We extend the model to the case of transparent samples that offer significant refractive index mismatch across the surface. We show that in these cases, the axial increase of depth of focus can be approximated by two Gaussian foci, one at the paraxial focus and one at an oblique focus. This model accurately describes experimentally observed depth profiles of reflective samples and transparent samples. We further extend the analysis to the case of thin transparent films to demonstrate that the model can be used in conjunction with physical measurements to produce accurate measurements of film thickness.

show abstract

Refractive index measurements of poly(methyl methacrylate) (PMMA) from 04–16 μm

Cited by 215 publications

References 16 publications

Large‐Size Transparent Wood for Energy‐Saving Building Applications

Large‐Size Transparent Wood for Energy‐Saving Building Applications

Distributed Humidity Sensing in PMMA Optical Fibers at 500 nm and 650 nm Wavelengths

A model for interpreting depth profiles of confocal Raman measurements in reflective and transmitting materials

Contact Info

Product

Resources

About