Ultrabroadband Reconstruction of the Refractive Index of Nonlinear Soft Glasses from Terahertz to Infrared Frequencies

2021 ◽  
Author(s):  
Adam Pacewicz ◽  
Jaroslaw Cimek ◽  
Bartlomiej Salski ◽  
Michal Walczakowski ◽  
Ryszard Buczynski
Keyword(s):  
Refractive Index ◽  
Infrared Frequencies ◽  
Soft Glasses

Rolled-up nanotechnology for the fabrication of three-dimensional fishnet-type GaAs-metal metamaterials with negative refractive index at near-infrared frequencies

2012 ◽  
Vol 100 (15) ◽  
pp. 151104 ◽  
Author(s):  
Andreas Rottler ◽  
Malte Harland ◽  
Markus Bröll ◽  
Stephan Schwaiger ◽  
Daniel Stickler ◽  
...  
Keyword(s):  
Refractive Index ◽  
Near Infrared ◽  
Negative Refractive Index ◽  
Three Dimensional ◽  
Infrared Frequencies

Empirical Electronic Polarizabilities for Use in Refractive Index Measurements III. Structures with Short [5]Ti–O and Vanadyl Bonds

2021 ◽  
Author(s):  
Robert D. Shannon ◽  
Reinhard X. Fischer
Keyword(s):  
Refractive Index ◽  
Oxygen Atom ◽  
Short Distance ◽  
Minimum Distance ◽  
Mean Value ◽  
Bond Valence ◽  
The Mean ◽  
Cation Coordination ◽  
Bond Valence Sum ◽  
Infrared Frequencies

ABSTRACT The electronic polarizabilities of most cations, such as Na+, Ca2+, Fe2+, Fe3+, and Zr4+, show a monotonic decrease as the cation coordination increases. However, polarizabilities of the ions [5]Ti4+, [5]V5+, and [6]V5+ show strong deviations from a regular decrease. In this paper we characterize the [5]Ti and vanadyl compounds by infrared frequencies, by the short [5]Ti4+– O, [5]V4+–O, [6]V4+–O, [5]V5+–O, and [6]V5+–O bonds and the polarizabilities of [5]Ti4+, [5]V4+, [6]V4+, [5]V5+, and [6]V5+ determined from refractive index measurements. Analysis of the structures of 18 compounds containing short [5]Ti–O bonds supports the concept of the short Ti–O bond being associated with the bond valence sum (omitting Ti) around the oxygen atom O*. The short Ti–O* bond occurs to satisfy the bond valence requirement of (O2–) of ∼2.0 vu. Plotting the [5]Ti–O* distances of 18 minerals versus the bond valence sum (BVS) around O* shows an approximately linear relationship. Extrapolation to BVS = 0 yields a minimum distance of 1.65 Å. The mean value is 1.693 Å. The mean short distances in V4+ vanadyl minerals are 1.597 Å (CN = 5) and 1.590 Å (CN = 6), whereas the mean short distance in five V5+ minerals is 1.647 Å (CN = 5) and in 14 V5+ minerals is 1.644 Å (CN = 6). We compare the polarizabilities of [5]Ti and [5,6]V4+ and [5,6]V5+ ions with the polarizabilities of [4]-coordinated Ti4+ ([4]Ti4+ ) and [6]-coordinated Ti4+ ([6]Ti4+ ) and of [4]-, [5]-, and [6]-coordinated V4+ and V5+ ([n]V4+ and [n]V5+) and hypothesize that the reduced polarizability of [5]Ti4+, [5]V5+, and [6]V5+ ions is caused by the short Ti–O* and V=O bonds.

scholarly journals Homogeneous Hyperbolic Systems for Terahertz and Far-Infrared Frequencies

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Leonid V. Alekseyev ◽  
Viktor A. Podolskiy ◽  
Evgenii E. Narimanov
Keyword(s):  
Refractive Index ◽  
Negative Refractive Index ◽  
Hyperbolic Systems ◽  
Far Infrared ◽  
Low Loss ◽  
Naturally Occurring ◽  
Ir Frequencies ◽  
Index Systems ◽  
Infrared Frequencies

We demonstrate that homogeneous naturally-occurring materials can form hyperbolic media, and can be used for nonmagnetic negative refractive index systems. We present specific realizations of the proposed approach for the THz and far-IR frequencies. The proposed structures operate away from resonance, thereby promising the capacity for low-loss devices.

scholarly journals Narrowband Perfect Absorber Based on Dielectric-Metal Metasurface for Surface-Enhanced Infrared Sensing

2020 ◽  
Vol 10 (7) ◽  
pp. 2295 ◽  
Author(s):  
Guilian Lan ◽  
Zhongxie Jin ◽  
Jinpeng Nong ◽  
Peng Luo ◽  
Caicheng Guo ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Sensors ◽  
Incident Angle ◽  
Structural Parameters ◽  
Refractive Index Sensor ◽  
Perfect Absorber ◽  
Refractive Index Sensitivity ◽  
Infrared Sensing ◽  
Surface Enhanced ◽  
Infrared Frequencies

We proposed a narrowband perfect absorber that was based on dielectric-metal metasurface for wide-band surface-enhanced infrared sensing. It is found that the narrowband perfect absorber can generate the hybrid guided modes with high quality-factor at infrared frequencies, which make the absorber highly sensitive to the surrounded analyte. Moreover, tuning the incident angle can actively modulate the resonant wavelength of absorber. Such an absorber with excellent features is employed to realize both refractive index sensing and infrared vibrational fingerprint sensing on a single substrate. It is demonstrated that a refractive index sensitivity of 1800 nm/RIU and figure of merit of 62 RIU−1 can be obtained as the refractive index sensor. While, as a surface enhanced infrared absorption spectroscopy substrate, two closed vibrational modes of analyte with nanometer thick layers can be effectively identified and selectively detected with 50-folds enhancement by actively tuning the incident angle without any change in the structural parameters (periodicity, width, height, and refractive index of the grating) of the device after fabricating. Our study offers a promising approach for designing high-performance surface-enhanced infrared optical sensors in the infrared region.

scholarly journals Design of triple-band metamaterial absorbers with refractive index sensitivity at infrared frequencies

2016 ◽  
Vol 24 (22) ◽  
pp. 25742 ◽  
Author(s):  
Jie Xu ◽  
Ziyi Zhao ◽  
Haochi Yu ◽  
Le Yang ◽  
Peng Gou ◽  
...  
Keyword(s):  
Refractive Index ◽  
Refractive Index Sensitivity ◽  
Metamaterial Absorbers ◽  
Index Sensitivity ◽  
Infrared Frequencies ◽  
Triple Band

TEM characterization of proton-exchanged LiNbO3 optical waveguides

1986 ◽  
Vol 44 ◽  
pp. 480-481
Author(s):  
W. E. Lee
Keyword(s):  
Refractive Index ◽  
Benzoic Acid ◽  
Optical Waveguides ◽  
Total Internal Reflection ◽  
Index Of Refraction ◽  
Optical Measurements ◽  
Lithium Ions ◽  
Wide Channel ◽  
Tem Characterization

An optical waveguide consists of a several-micron wide channel with a slightly different index of refraction than the host substrate; light can be trapped in the channel by total internal reflection.Optical waveguides can be formed from single-crystal LiNbO3 using the proton exhange technique. In this technique, polished specimens are masked with polycrystal1ine chromium in such a way as to leave 3-13 μm wide channels. These are held in benzoic acid at 249°C for 5 minutes allowing protons to exchange for lithium ions within the channels causing an increase in the refractive index of the channel and creating the waveguide. Unfortunately, optical measurements often reveal a loss in waveguiding ability up to several weeks after exchange.

Light microscopy of ceramics

1993 ◽  
Vol 51 ◽  
pp. 908-909
Author(s):  
Walter C. McCrone
Keyword(s):  
Refractive Index ◽  
Light Microscopy ◽  
Light Microscope ◽  
Polarized Light ◽  
Refractive Indices ◽  
Complete Coverage ◽  
The Subject ◽  
Lower Refractive Index

An excellent chapter on this subject by V.D. Fréchette appeared in a book edited by L.L. Hench and R.W. Gould in 1971 (1). That chapter with the references cited there provides a very complete coverage of the subject. I will add a more complete coverage of an important polarized light microscope (PLM) technique developed more recently (2). Dispersion staining is based on refractive index and its variation with wavelength (dispersion of index). A particle of, say almandite, a garnet, has refractive indices of nF = 1.789 nm, nD = 1.780 nm and nC = 1.775 nm. A Cargille refractive index liquid having nD = 1.780 nm will have nF = 1.810 and nC = 1.768 nm. Almandite grains will disappear in that liquid when observed with a beam of 589 nm light (D-line), but it will have a lower refractive index than that liquid with 486 nm light (F-line), and a higher index than that liquid with 656 nm light (C-line).

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