Does the Refractive Index of Materials Change with Temperature and Wavelength?

In summary: Some notes: wavelength ranges are typically specified in terms of nanometers (nm), meters (m), or kilometers (km).You could also try searching for 'permittivity' or 'thermo-optic coefficient'.
  • #1
sjumesh
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Hello all,
I want to know that refractive index of materials like cooper, zinc, aluminium, teflon, PMMA varies with the application of heat from room to 100°C and for negative temperatures 77k to 300k.
thanks in advance.
 
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  • #2
Welcome to PF;
The answer is yes - the refractive index of materials like that depend on temperature.
I don't know how you'd find out the specific temperature dependence of a material across the entire temperature range you are interested in - it is likely there will be useful information in an engineering and material science desk reference, and the rest will need a literature hunt. Teflon and PMMA are quite complicated but they are all well studied materials - I'd be surprised if the information was not available.

Some notes:
I am guessing you are not used to scientific conversations. One of the goals of this forum is to help people better communicate in a scientific way. To that end:

"a temperature of 77k" reads like this: "a temperature of 77000 Kelvin"
... because the lower case "k" is the metric prefix "kilo", and a temperature without explicit units is usually taken to be absolute "Kelvin".
(It is a very common shorthand to refer to kilo-something as a so-much "kay", with the actual unit implied by the situation.)
The SI symbol for "Kelvin" is an upper case "K".

It is not possible to have a negative temperature in Kelvins though. Presumably you are thinking of negative degrees centigrade?

300K would be a common approximation for "room temperature" - about 27degC, actually a tad on the warm side - but i.e. not negative.

In general, it is best to pick a unit and stick to it within the same bit of writing. Jumping around the units tends to lead to confusion ... or, at least, it makes the reader work harder than they need to.

* You wanted to know about the temperature range: 77 to 373K or -196 to 100 degC.
 
  • #3
Hello Simon Bridge,
At first thanks for your valuable reply.
yeah i am not used to scientific conversations and its my first post on the forum.
Sorry for the confusion. its about the temperature range: 77 to 373K or -196 to 100 degC. i wanted to know.
i will follow up in future as you told.
thanks again
 
  • #4
No worries - cannot expect everyone to get it right first time ... ;)
It would be possible to provide a better answer if we knew the context for the question.
 
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  • #5
The index of refraction of these substances varies only little in this temperature range. The main change is due to thermal expansion. So if you find the value of ##n(T_1)## for some temperature ##T_1## and it's density ##\rho(T_1)## then the index of refraction at another temperature is in good approximation ##n(T_2)=n(T_1)\cdot \rho(T_2)/\rho(T_1)##.
 
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  • #6
sjumesh said:
Hello all,
I want to know that refractive index of materials like cooper, zinc, aluminium, teflon, PMMA varies with the application of heat from room to 100°C and for negative temperatures 77k to 300k.
thanks in advance.

This question is too vague to answer- what wavelength range?

some links of relevance:
http://srdata.nist.gov/gateway/gateway?property=refractive+index&proft=Submit&rddesc=desc
http://www.nist.gov/pml/div685/grp03/theory_calculation.cfm [Broken]
https://www.google.com/url?sa=t&rct...StOgtjkk_OvJ01w&bvm=bv.84349003,d.aWw&cad=rja
http://www.google.com/url?sa=t&rct=...=JvP0xwyYu8pKsumK3xbZdA&bvm=bv.84349003,d.aWw

Depending on what waveband you are interested in, you could search for 'permittivity' rather than 'refractive index', and 'thermo-optic coefficient' rather than 'temperature dependence'.
 
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  • #7
Hello Andy,
thanks for your reply.
i will check the above mentioned links.
I use 1550nm wavelength range.
 

1. What is the refractive index of a material?

The refractive index of a material is a measure of how much the speed of light is reduced when it passes through that material. It is a dimensionless number that describes the ratio of the speed of light in a vacuum to the speed of light in the material.

2. How is the refractive index of a material determined?

The refractive index of a material is typically determined by measuring the angle of refraction when a beam of light passes through the material and comparing it to the angle of incidence. This can be done using a device called a refractometer or by using mathematical calculations based on the material's physical properties.

3. What factors affect the refractive index of a material?

The refractive index of a material can be affected by various factors such as temperature, pressure, and the wavelength of light passing through it. Additionally, the chemical composition and molecular structure of the material can also impact its refractive index.

4. How does the refractive index of a material affect light?

The refractive index of a material determines the amount of bending or refraction that occurs when light passes through it. This is why objects appear distorted when viewed through materials with different refractive indexes, such as water or glass.

5. Why is the refractive index of a material important in science?

The refractive index of a material is important in science because it can provide valuable information about the physical and chemical properties of the material. It is also crucial in various fields such as optics, spectroscopy, and materials science, where the interaction of light with different materials is studied and applied in different technologies and applications.

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