Towards photonic time-crystals: observation of a femtosecond time-boundary in the refractive index

2021 ◽  
Author(s):  
Eran Lustig ◽  
Soham Saha ◽  
Eliyahu Bordo ◽  
Clayton DeVault ◽  
Sarah N. Chowdhury ◽  
...  
Keyword(s):  
Refractive Index ◽  
Time Boundary ◽  
Time Crystals

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).

On the refractive index of rutile

1992 ◽  
Vol 139 (2) ◽  
pp. 163 ◽  
Author(s):  
M.R. Shenoy ◽  
R.M. de la Rue
Keyword(s):  
Refractive Index

Modification of optical properties of PC-PBT/Cr2O3 and PC-PBT/CdS nanocomposites by gamma irradiation

2020 ◽  
Vol 92 (2) ◽  
pp. 20402
Author(s):  
Kaoutar Benthami ◽  
Mai ME. Barakat ◽  
Samir A. Nouh
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Band Gap ◽  
Color Difference ◽  
Band Gap Energy ◽  
Polybutylene Terephthalate ◽  
Γ Irradiation ◽  
Gap Energy ◽  
Vis Spectroscopy ◽  
Oxygen Atoms

Nanocomposite (NCP) films of polycarbonate-polybutylene terephthalate (PC-PBT) blend as a host material to Cr2O3 and CdS nanoparticles (NPs) were fabricated by both thermolysis and casting techniques. Samples from the PC-PBT/Cr2O3 and PC-PBT/CdS NCPs were irradiated using different doses (20–110 kGy) of γ radiation. The induced modifications in the optical properties of the γ irradiated NCPs have been studied as a function of γ dose using UV Vis spectroscopy and CIE color difference method. Optical dielectric loss and Tauc's model were used to estimate the optical band gaps of the NCP films and to identify the types of electronic transition. The value of optical band gap energy of PC-PBT/Cr2O3 NCP was reduced from 3.23 to 3.06 upon γ irradiation up to 110 kGy, while it decreased from 4.26 to 4.14 eV for PC-PBT/CdS NCP, indicating the growth of disordered phase in both NCPs. This was accompanied by a rise in the refractive index for both the PC-PBT/Cr2O3 and PC-PBT/CdS NCP films, leading to an enhancement in their isotropic nature. The Cr2O3 NPs were found to be more effective in changing the band gap energy and refractive index due to the presence of excess oxygen atoms that help with the oxygen atoms of the carbonyl group in increasing the chance of covalent bonds formation between the NPs and the PC-PBT blend. Moreover, the color intensity, ΔE has been computed; results show that both the two synthesized NCPs have a response to color alteration by γ irradiation, but the PC-PBT/Cr2O3 has a more response since the values of ΔE achieved a significant color difference >5 which is an acceptable match in commercial reproduction on printing presses. According to the resulting enhancement in the optical characteristics of the developed NCPs, they can be a suitable candidate as activate materials in optoelectronic devices, or shielding sheets for solar cells.

Refractive Index for Atomic Waves: Theory and Detailed Calculations

1997 ◽  
Vol 7 (4) ◽  
pp. 523-541 ◽  
Author(s):  
C. Champenois ◽  
E. Audouard ◽  
P. Duplàa ◽  
J. Vigué
Keyword(s):  
Refractive Index

Investigating the Nonlinear Optical Response of Pepper Oil under Low Power Irradiation with Continuous Wave Visible Laser Beam

2020 ◽  
pp. 131-138
Keyword(s):  
Refractive Index ◽  
Nonlinear Refractive Index ◽  
Nonlinear Optical ◽  
Continuous Wave ◽  
Diffraction Integral ◽  
Visible Laser ◽  
Limiting Property ◽  
Kirchhoff Diffraction Integral ◽  
Theoretical Results ◽  
Good Agreement

The nonlinear optical properties of pepper oil are studied by diffraction ring patterns and Z-scan techniques with continuous wave beam from solid state laser at 473 nm wavelength. The nonlinear refractive index of the sample is calculated by both techniques. The sample show high nonlinear refractive index. Based on Fresnel-Kirchhoff diffraction integral, the far-field intensity distributions of ring patterns have been calculated. It is found that the experimental results are in good agreement with the theoretical results. Also the optical limiting property of pepper oil is reported. The results obtained in this study prove that the pepper oil has applications in nonlinear optical devices.

Elemen Merentasi Sempadan Masa Dalam “Ghiyath al-Umam” Karya Imam al-Haramayn al-Juwayniyy

Sains Insani ◽  
2018 ◽  
Vol 3 (1) ◽  
pp. 52-60
Author(s):  
Mohammad Zaini Yahaya ◽  
Muhammad Adib Samsudin ◽  
Mohd Izhar Ariff Mohd Kashim
Keyword(s):  
Qualitative Study ◽  
Document Analysis ◽  
The People ◽  
Time Boundary

In the study school of thought, an exposure to the context of across the time boundary known as "al-fiqh al-taqdiri" is a special feature in the formation of the Hanafi sect. It is also a feature shared by other sects including the Syafie sect. The authors chose the book of "Ghiyath al-Umam" by Imam al-Haramayn al-Juwayniyy (419H-478H) for this study as the book was loaded with elements across the time compared to his other books. This study is a qualitative study and the design is document analysis. The study of Ghiyath al-Umam's book shows how far Imam al-Haramayn's imagination that has not been reflected by most of the people at his time. But some have already happened now and some might happen in the future.Keywords: civilization, futuristics, Syafie sect ABSTRAK: pengajian sejarah mazhab kita biasa didedahkan bahawa fiqh merentasi sempadan masa yang dikenali sebagai “al-fiqh al-taqdiri” merupakan ciri istimewa dalam pembentukan mazhab Hanafi. Hakikatnya dengan berlalunya zaman ia turut menjadi ciri yang dikongsi bersama oleh mazhab-mazhab lain termasuk mazhab Syafie. Untuk melihat kebenaran teori ini penulis memilih kitab “Ghiyath al-Umam” karangan Imam al-Haramayn al-Juwayniyy (419H-478H). Imam al-Haramayn merupakan antara tokoh terawal yang tersohor dalam bidang fiqh syafie dan usul al-fiqh di samping bidang ilmu kalam. Karya-karya beliau dalam bidang fiqh mazhab Syafie dan usul al-fiqh aliran mutakallimin menjadi sumber utama dalam disiplin masing-masing. Pandangan-pandangan beliau sangat berautoriti dan dinukilkan oleh para ulama muhaqqiqun seperti Imam al-Nawawiyy dalam fiqh Syafie dan Fakhr al-Din al-Raziyy dalam bidang usul al-fiqh. Justeru beliau ialah tokoh yang sangat bersesuaian untuk tujuan kajian ini. Kitab Ghiyath al-Umam dijadikan fokus kajian memandangkan kitab ini sarat dengan elemen merentasi masa berbanding kitab-kitab beliau yang lain. Kajian ini merupakan kajian kualitatif dan reka bentuknya adalah analisis dokumen. Kajian terhadap kitab Ghiyath al-Umam dapat menunjukkan betapa jauhnya imiginasi Imam al-Haramayn yang tidak tergambar oleh sebahagian besar manusia ketika itu. Namun sebahagiannya sudah pun berlaku pada masa ini dan sebahagiannya mungkin akan berlaku pada masa akan datang.Kata Kunci: peradaban, futuristik, fiqh mazhab Syafie

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