Design of freeform LED lens with large light deflection angle for road lighting application

Author(s):  
Shaoyun Yin ◽  
Zhongxun Wang ◽  
Xiuhui Sun ◽  
Liangping Xia ◽  
Hui Pang ◽  
...  
2019 ◽  
Vol 34 (05) ◽  
pp. 1950040 ◽  
Author(s):  
Amrita Bhattacharya ◽  
Alexander A. Potapov

Tsukamoto [N. Tsukamoto, Phys. Rev. D 95, 064035 (2017)] developed a method, which is an improvement over that of Bozza [V. Bozza, Phys. Rev. D 66, 103001 (2002)], for calculating light deflection angle in the strong gravity field of a spherically symmetric static spacetime. The method is directly applicable to the massless Ellis–Bronnikov wormhole (EBWH), while Bozza’s method is not applicable. We wish to show that it is still possible to obtain the same deflection angle by applying Bozza’s method but only in an indirect way, that is, first calculate the deflection by the parent massive EBWH and then take its massless limit.


Author(s):  
A.N. Alexandrov ◽  
V.I. Zhdanov ◽  
V.M. Sliusar

We propose a new test of the Einstein’s formula for the gravitational light deflection using the Galactic microlensing. In this classical formula, the deflection angle ∆ϕ is inversely proportional to the impact parameter p of incoming photons travelling from infinity.


2011 ◽  
Vol 19 (S4) ◽  
pp. A716 ◽  
Author(s):  
Shang Wang ◽  
Kai Wang ◽  
Fei Chen ◽  
Sheng Liu

2017 ◽  
Vol 72 (6) ◽  
pp. 577-583
Author(s):  
Sarani Chakraborty ◽  
A.K. Sen

AbstractIt has been shown by various authors that gravomagnetic field can produce lensing effect. The effect of such a gravitational body with gravomagnetic mass on the trajectory of light ray is discussed in this paper. The light deflection angle has been calculated in the present works, considering upto fourth order terms. Schwarzschild light deflection angle can be obtained from this expression, by setting gravomagnetic mass equals to zero. However, for a hypothetical massless, gravomagnetic monopole, the light deflection angle does not reduce to zero.


2013 ◽  
Vol 2013 ◽  
pp. 1-4
Author(s):  
Debasish Saha ◽  
Amarjit Tamang ◽  
Ramil Izmailov ◽  
Carlo Cattani ◽  
Kamal K. Nandi

We resolve here an outstanding problem plaguing conformal gravity in its role in making consistent astrophysical predictions. Though its static spherically symmetric solution incorporates all the successes of Schwarzschild gravity, the fit to observed galactic rotation curves requires γ>0, while the observed increase in the Schwarzschild light deflection by galaxies appears to demand γ<0. Here we show that, contrary to common knowledge, there is an increase in the Schwarzschild deflection angle in the vicinity of galaxies due purely to the effect of γ>0, when the idea of the Einstein-Strauss vacuole model is employed. With the inconsistency now out of the way, conformal gravity should be regarded as a good theory explaining light deflection by galaxies.


Author(s):  
Wajiha Javed ◽  
Jameela Abbas ◽  
Yashmitha Kumaran ◽  
Ali Övgün

The principal objective of this project is to investigate the gravitational lensing by asymptotically flat black holes in the framework of Horndeski theory in weak field limits. To achieve this objective, we utilize the Gauss-Bonnet theorem to the optical geometry of asymptotically flat black holes and applying the Gibbons-Werner technique to achieve the deflection angle of photons in weak field limits. Subsequently, we manifest the influence of plasma medium on deflection of photons by asymptotically flat black holes in the context of Horndeski theory. We also examine the graphical impact of deflection angle on asymptotically flat black holes in the background of Horndeski theory in plasma as well as non-plasma medium.


2020 ◽  
Vol 80 (12) ◽  
Author(s):  
Rahul Kumar ◽  
Shafqat Ul Islam ◽  
Sushant G. Ghosh

AbstractAmong the higher curvature gravities, the most extensively studied theory is the so-called Einstein–Gauss–Bonnet (EGB) gravity, whose Lagrangian contains Einstein term with the GB combination of quadratic curvature terms, and the GB term yields nontrivial gravitational dynamics in $$ D\ge 5$$ D ≥ 5 . Recently there has been a surge of interest in regularizing, a $$ D \rightarrow 4 $$ D → 4 limit of, the EGB gravity, and the resulting regularized 4D EGB gravity valid in 4D. We consider gravitational lensing by Charged black holes in the 4D EGB gravity theory to calculate the light deflection coefficients in strong-field limits $$\bar{a}$$ a ¯ and $$\bar{b}$$ b ¯ , while former increases with increasing GB parameter $$\alpha $$ α and charge q, later decrease. We also find a decrease in the deflection angle $$\alpha _D$$ α D , angular position $$\theta _{\infty }$$ θ ∞ decreases more slowly and impact parameter for photon orbits $$u_{m}$$ u m more quickly, but angular separation s increases more rapidly with $$\alpha $$ α and charge q. We compare our results with those for analogous black holes in General Relativity (GR) and also the formalism is applied to discuss the astrophysical consequences in the case of the supermassive black holes Sgr A* and M87*.


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