In the last decades, strong GL regained more attention, ,, ,. Later, Bozza et al. extended the previous analysis for any general static, asymptotically spherically symmetric spacetime. After that Bozza et al. developed an useful method to obtain the deflection angle of light rays by a compact object in the strong field limit, and they found the logarithmic divergence of the deflection angle for Schwarzschild BH in the strong field region. derived the exact lens equation regardless of background spacetime for arbitrary large value of deflection angle. Leter, Virbhadra and Ellis , and Frittelli et al. Strong GL was first investigated by darwin in 1959 that the photons rays passing near to a black hole (BH) may have a large deflection angle and could make multiple loops around the BH before reaching to the observer.

Accordingly, the deflection angle of photon rays, the GL can be divided into scenarios, one of them is weak GL when the deflection angle is small, and another one is strong GL, when the deflection angle of photon rays becomes so larger.

It has been successfully employed to explain for probing the strong characterization of gravity. One of the most powerful and important tools in astrophysics as well as cosmology is gravitational lensing(GL), which deals with the deflection light rays passing through the gravitational field.

It is further concluded that the Van der Waals black hole can be quantitatively distinguished from the other ordinary black hole such as Schwarzschild Ads black hole via shadow and strong lensing observations. It is concluded that the Van der Waals parameters a, b and homogeneous plasma medium have a significant effect on both the shadows and strong gravitational lensing. Further, we discuss the observable quantities angular position θ ∞, separation S and magnification r m a g by taking the example of a supermassive black hole M 8 7 ∗ in the context of Van der Waals black hole and compared to the other ordinary black hole such as Schwarzschild Ads black hole in the strong field limit with the effects of homogeneous plasma. We also find that the deflection angle in the strong field limit by the Van der Waals black hole with the homogeneous plasma is greater than that of the Vacuum medium. We observe that the photon sphere radius, deflection limit coefficients and deflection angle in the strong field are highly affected by the presence of a homogeneous plasma medium. We also discuss the strong gravitational lensing in a homogeneous plasma medium. We also observe that the radius of the shadow in a homogeneous plasma medium increases when parameter σ = ω p ω ∞ (the ratio of plasma frequency and photon frequency) increases and the radius of the shadow inhomogeneous plasma medium is larger than the vacuum medium. We find that both the Van der Waals parameters a and b have a significant effect on the shadow of the black hole. In this paper, we first analyze the horizon structure of the Van der Waals (VdW) black hole and then investigate its shadow in the absence of a plasma medium as well as the presence of a homogeneous plasma medium.

Van der waals equation calculator