General interferometric approaches based on variable incidence angle method for refractive index and thickness measurement of birefringent multi-medium objects

2004 ◽  
Author(s):  
M. Sadik
Keyword(s):  
Refractive Index ◽  
Incidence Angle ◽  
Thickness Measurement ◽  
Angle Method

scholarly journals Alternative approach to variable wavelength interferometry

2020 ◽  
Vol 12 (4) ◽  
pp. 112
Author(s):  
Dariusz Litwin ◽  
Kamil Radziak ◽  
Jacek Galas
Keyword(s):  
Classical Method ◽  
Incidence Angle ◽  
Visible Spectrum ◽  
Thickness Measurement ◽  
Optical Path Difference ◽  
Zero Order ◽  
Optical Systems ◽  
Fast Variable ◽  
Current Increase ◽  
Measurement Science

The paper presents an alternative technique of calculation the retardance of quartz waveplates. The technique utilizes continuously tuned wavelength, which identifies the zero-order fringe and simultaneously facilitates high repeatability of the optical path difference across the entire visible spectrum. Unlike in classical method, precise monitoring of the current increase or decrease of the interference order is not required. The discussion includes comparison of the standard deviation between the classical and novel approaches. Full Text: PDF ReferencesM. Pluta, Advanced Light Microscopy (Vol. 3, PWN, Elsevier, Warszawa-Amsterdam-London-New York-Tokyo, 1993). DirectLinkM. Pluta, "Object-adapted variable-wavelength interferometry. I. Theoretical basis", Journal of Opt. Soc. Am., A4(11), 2107 (1987). CrossRef M. Pluta, "Variable wavelength microinterferometry of textile fibres", J. Microscopy, 149(2), 97 (1988). CrossRef M. Pluta, "On double‐refracting microinterferometers which suffer from a variable interfringe spacing across the image plane", Journal of Microscopy, 145(2), 191 (1987). CrossRef M. Pluta, "Variable wavelength interferometry of birefringent retarders", Opt. Laser Technology, 19(3), 131 (1987). CrossRef D. Litwin, A. M. Sadik, "Computer-aided variable wavelength Fourier transform polarizing microscopy of birefringent fibers", Optica Applicata 28(2), 139 (1998). DirectLink A. Sadik, W. A. Ramadan, D. Litwin, "Variable incidence angle method combined with Pluta polarizing interference microscope for refractive index and thickness measurement of single-medium fibres", Measurement Science and Technology, IOP Publishing 14(10), 1753 (2003). CrossRef J. Galas, S. Sitarek; D. Litwin; M. Daszkiewicz, "Fringe image analysis for variable wavelength interferometry", Proc. SPIE 10445, 1044504 (2017). CrossRef D. Litwin, J. Galas, N. Błocki, "Automated variable wavelength interferometry in reflected light mode", Proc.SPIE 6188, 61880F (2006). CrossRef J. Galas, D. Litwin, M. Daszkiewicz, "New approach for identifying the zero-order fringe in variable wavelength interferometry", Proc. SPIE 10142, 101421R (2016). CrossRef D. Litwin, J. Galas, M. Daszkiewicz, T. Kryszczyński, A. Czyżewski, K. Radziak, "Dedicated optical systems of the Institute of Applied Optics", Phot. Lett. Pol., vol. 11, no. 2, pp. 29-31, (2019). CrossRef D. Litwin, K. Radziak, J. Galas "A fast variable wavelength interferometer", Proc. SPIE 11581, 115810O, (2020). CrossRef

scholarly journals Ultrasensitive Biosensor with Hyperbolic Metamaterials Composed of Silver and Zinc Oxide

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2220
Author(s):  
Shuhan Chen ◽  
Shiqi Hu ◽  
Yichen Wu ◽  
Dingnan Deng ◽  
Yunhan Luo ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Refractive Index ◽  
Figure Of Merit ◽  
Incidence Angle ◽  
Interaction Strength ◽  
Physical Reason ◽  
Filling Fraction ◽  
Electric Field Amplitude ◽  
Spr Sensor ◽  
Biochemical Sensing

We propose a hyperbolic metamaterial-based surface plasmon resonance (HMM-SPR) sensor by composing a few pairs of alternating silver (Ag) and zinc oxide (ZnO) layers. Aiming to achieve the best design for the sensor, the dependence of the sensitivity on the incidence angle, the thickness of the alternating layer and the metal filling fraction are explored comprehensively. We find that the proposed HMM-SPR sensor achieves an average sensitivity of 34,800 nm per refractive index unit (RIU) and a figure of merit (FOM) of 470.7 RIU−1 in the refractive index ranging from 1.33 to 1.34. Both the sensitivity (S) and the FOM show great enhancement when compared to the conventional silver-based SPR sensor (Ag-SPR). The underlying physical reason for the higher performance is analyzed by numerical simulation using the finite element method. The higher sensitivity could be attributed to the enhanced electric field amplitude and the increased penetration depth, which respectively increase the interaction strength and the sensing volume. The proposed HMM-SPR sensor with greatly improved sensitivity and an improved figure of merit is expected to find application in biochemical sensing due to the higher resolution.

Influence of Seawater Refractive Index on the Precision of Oil Film Thickness Measurement by Differential Laser Triangulation

2015 ◽  
Vol 42 (4) ◽  
pp. 0408004
Author(s):  
耿云飞 Geng Yunfei ◽  
陈曦 Chen Xi ◽  
金文 Jin Wen ◽  
张惠群 Zhang Huiqun ◽  
邬海强 Wu Haiqiang ◽  
...  
Keyword(s):  
Refractive Index ◽  
Film Thickness ◽  
Thickness Measurement ◽  
Laser Triangulation ◽  
Oil Film ◽  
Film Thickness Measurement

INVESTIGATIONS ON AZO/Al/AZO MULTILAYER STRUCTURE GROWN AT ROOM TEMPERATURE

2018 ◽  
Vol 25 (08) ◽  
pp. 1950033
Author(s):  
SAAD AMARA ◽  
MOHAMED BOUAFIA
Keyword(s):  
Refractive Index ◽  
Room Temperature ◽  
Incidence Angle ◽  
Metal Layer ◽  
Complex Refractive Index ◽  
Visible Range ◽  
Light Emitting ◽  
The Real ◽  
Pl Emission

In this work we investigate the effect of metal layer in the Al-doped ZnO (AZO)/Al/AZO structure. AZO and Al thin films are deposed successively at room temperature using DC magnetron sputtering by rotating the substrate holder without breaking the vacuum. The optical characterization of AZO/Al/AZO structure was performed by the spectroscopic ellipsometry under different incidence angles (55[Formula: see text], 65[Formula: see text] and 75[Formula: see text]). For the AZO monolayer structure, it was found that the complex refractive index and the complex permittivity coefficient varied differently according to the incidence angle. The addition of Al layer (5[Formula: see text]nm thicknesses) in this monostructure reduces significantly this influence on the measurement, homogenizes the real refractive index variation and significantly reduces the real electrical coefficient permittivity in the visible range. In addition, the obtained depolarization values confirm the results of the AFM roughness revealing that the Al layer addition makes the surface smoother so that it meets the required conditions as the bottom electrode of organic light emitting diodes. The photoluminescence (PL) measurements indicate that the Al layer alters the PL emission. Actually, the Al layer enhances subsequently the PL emission and promotes the blue and red emission.

Refractive index and geometrical thickness measurement of thin optical samples by a transmitted Gaussian beam

2014 ◽  
Vol 53 (30) ◽  
pp. 6993 ◽  
Author(s):  
Octavio Olvera-R ◽  
Moisés Cywiak ◽  
Joel Cervantes-L ◽  
David Cywiak
Keyword(s):  
Refractive Index ◽  
Gaussian Beam ◽  
Thickness Measurement

scholarly journals Non-destructive thickness measurement of thermal barrier coatings using terahertz radiation

2021 ◽  
Author(s):  
Luis Isern ◽  
Andrew J. Waddie ◽  
Christine Chalk ◽  
Andrew J. Moore ◽  
John R. Nicholls
Keyword(s):  
Refractive Index ◽  
Thermal Barrier Coatings ◽  
Cross Sections ◽  
Thickness Distribution ◽  
Thickness Measurement ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Thickness Variations ◽  
Thickness Measurements ◽  
Non Destructive

AbstractA non-destructive thickness measurement technique based on terahertz (THz) reflectivity was successfully deployed to interrogate 7 wt.% yttria-stabilised zirconia thermal barrier coatings (TBCs) produced by electron-beam physical vapour deposition (EB-PVD). The THz technique was shown to produce accurate thickness maps for different samples with a resolution of 1 × 1 mm over a surface of 65 × 20 mm that were compared with direct examination of key cross-sections. All thickness measurements on different samples were calculated using a single value of refractive index. Small defects characteristic of EB-PVD, such as “carrot growths” and variations on column inclination, were evaluated and did not produce significant variations in the refractive index of the TBC. Moreover, the thickness maps correctly display thickness variations that are a consequence of the point-source nature of EB-PVD evaporation. In summary, this paper demonstrates the technique can be successfully deployed on large surfaces, and across different coatings of the same material produced under the same deposition conditions. It is shown that a single n value is required to map the thickness distribution for all samples. This combination of qualities indicates the potential of the technique for in-line control of TBC manufacture.

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