# Scattering from lossy medium whose refractive index is unity

• Swamp Thing
In summary, a thin transparent plate with an equal refractive index to air and a small loss can cause bending of light passing through it, even within the specified constraints. This process is similar to total internal reflection, but with the added factor of absorption that can result in refraction-like bending.

#### Swamp Thing

Consider a thin transparent plate surrounded by air. The plate's refractive index is exactly the same as the air's, but it does have a small loss (say of the order of 1%).

Let the plate be vertical and normal to our "page" or your computer screen. A laser beam passes through the plate at an acute angle such as 5 degrees, say from the lower right to the upper left.

Now is there any mechanism in this system by which some of the light would be scattered towards the upper right? (FWIW, I arrived at this conjecture while following some train of thought that probably wouldn't interest anyone here).

If there is such a process, where can I read more about it? Does it have a name? Would the scattered energy form a beam similar in width to the incident one?

For an absorptive material, the index of refraction becomes a complex quantity. Nevertheless it won't lead to scattering out of the plane defined by the normal to the surface and the incidence vector.

Thank you!
In my post, the question is about scattering within (consistent with) the constraint that you specified, but in a direction that is still counter intuitive. The direction I am asking about is similar to total internal reflection but with refractive index being the same as air.

You note that absorption is included in a complex coefficient -- so if I understand correctly, the loss component can result in refraction-like bending?

Swamp Thing said:
You note that absorption is included in a complex coefficient -- so if I understand correctly, the loss component can result in refraction-like bending?
Yes

Swamp Thing

## 1. What is scattering from a lossy medium with a refractive index of unity?

Scattering is the process by which electromagnetic waves are redirected in different directions due to interaction with particles in a medium. A lossy medium is one that absorbs energy from the electromagnetic wave, causing it to lose intensity. A refractive index of unity means that the medium has the same refractive index as the surrounding medium, which has a value of 1.

## 2. How does the refractive index affect scattering in a lossy medium?

The refractive index of a medium determines how much the speed of light is reduced when it passes through that medium. In a lossy medium with a refractive index of unity, the scattered waves will have the same speed and direction as the incident waves, but their intensity will be reduced due to absorption.

## 3. What factors influence the amount of scattering in a lossy medium with a refractive index of unity?

The amount of scattering in a lossy medium with a refractive index of unity is influenced by several factors, including the size and shape of the particles in the medium, the wavelength of the incident wave, and the angle of incidence. Additionally, the absorption coefficient of the medium and the dielectric properties of the particles can also affect scattering.

## 4. How is scattering from a lossy medium with a refractive index of unity measured?

Scattering from a lossy medium with a refractive index of unity can be measured using techniques such as light scattering spectroscopy, which analyzes the intensity and angle of the scattered light to determine the size and concentration of particles in the medium. Other methods, such as dynamic light scattering, can also be used to measure the scattered light and characterize the properties of the medium.

## 5. What are some applications of studying scattering from lossy media with a refractive index of unity?

Scattering from lossy media with a refractive index of unity has many applications in various fields, such as material science, environmental monitoring, and biomedical imaging. It can be used to study the properties of particles in a medium, such as their size and concentration, which can provide valuable information in these fields. Additionally, understanding scattering from lossy media can also aid in the development of more efficient and accurate measurement techniques.