نتایج جستجو برای: effective refractive index

تعداد نتایج: 1060496  

2016
KKA Devi CH Ng

A high gain patch antenna inspired by 4 layers of negative refractive index (NRI) metamaterial (MTM) superstrate is proposed to operate at downlink radio frequency (RF) band (935MHz to 960MHz) of GSM 900). The MTM unit cell consists of a nested split ring resonator (SRR) on one side and strip line laminated on other side of FR4 substrate. The effective permeability and permittivityof the unit c...

Journal: :Journal of biomedical optics 2013
Kenichiro Yoshida Kohji Ohkubo Nobutoshi Ojima Kayoko Iwata

We adapted the critical angle method for measuring rough surfaces under partial contact to acquire an in vivo skin refractive index (RI). Assuming that the total reflection is the simple sum of reflection from areas that are in contact and reflection from those that are not in contact, the RI can be estimated even for partial contact with a rough surface. We found that cheek skin is sufficientl...

2017
O. Saoudi N. Ghaouar S. Ben Salah T. Othman

In this work, we are interested in the denaturation process of a laccase from Tramates versicolor via the determination of the refractive index, the refractive index increment and the specific volume in various media. The measurements were carried out using an Abbe refractometer. We have shown that the refractive index increment values obtained from the slope of the variation of the refractive ...

Journal: :Applied optics 2011
Tuomas Hieta Mikko Merimaa Markku Vainio Jeremias Seppä Antti Lassila

We present a laser-based system to measure the refractive index of air over a long path length. In optical distance measurements, it is essential to know the refractive index of air with high accuracy. Commonly, the refractive index of air is calculated from the properties of the ambient air using either Ciddor or Edlén equations, where the dominant uncertainty component is in most cases the ai...

Journal: :Optics letters 2015
Sung W Kim Ki Ju Yee Maxim Abashin Lin Pang Yeshaiahu Fainman

We designed, fabricated, and characterized a dielectric metamaterial lens created by varying the density of subwavelength low refractive index nanoholes in a high refractive index substrate, resulting in a locally variable effective refraction index. It is shown that a constructed graded index lens can overcome diffraction effects even when the aperture/wavelength (D/λ) ratio is smaller than 40...

Journal: :Physical review letters 2012
Kejie Fang Zongfu Yu Shanhui Fan

We show that when the refractive index of a photonic system is harmonically modulated, the phase of the modulation introduces an effective gauge potential for photons. This effective gauge potential can be used to create a photonic Aharonov-Bohm effect. We show that the photonic Aharonov-Bohm effect provides the optimal mechanism for achieving complete on-chip nonmagnetic optical isolation.

2008
Jong Kyu Kim Sameer Chhajed Martin F. Schubert E. Fred Schubert Arthur J. Fischer Mary H. Crawford Jaehee Cho Hyunsoo Kim Cheolsoo Sone

In photonics and optics, the refractive index of a material, first introduced by Isaac Newton as the optical density, is the most fundamental material constant. Since the refractive index determines refraction and reflection occurring at the boundary between two media, it is a critical parameter for the design of optical components, such as distributed Bragg reflectors (DBRs), omnidirectional r...

2017
MUHAMMAD ARIF BIN JALIL

This study presents the modelling, simulation, and characterization of the Fiber Bragg grating (FBG) on maximum reflectivity, bandwidth, the effect of applied strain to the wavelength shift, ŽB and sensitivity of the wavelength shift with strain for optical sensing system. In this study, a commercial FBG with the center wavelength of 1550nm is used in order to measure the spectral response of F...

Journal: :Physical review letters 2010
Valery E Lobanov Yaroslav V Kartashov Lluis Torner

We put forward a new approach to generate stable, fully three-dimensional light bullets, which is based on the matching of the intrinsic material dispersion with a suitable effective diffraction. The matching is achieved in adequate waveguide arrays whose refractive index is periodically modulated along the direction of light propagation. We show that by using nonconventional, out-of-phase long...

1998
R. Serna J. C. G. de Sande C. N. Afonso

Spectroscopic ellipsometry together with an effective medium model is used to determine simultaneously the effective refractive index, thickness, and metal volume fraction of thin nanocomposite films. The films are formed by Bi nanocrystals embedded in amorphous matrices, either semiconducting ~Ge! or dielectric (Al2O3). For the Bi:Ge films ~metal in an absorbing host!, the values obtained for ...

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