How to emit 3.2 micrometer wavelength

[Vincent L]

Good day!
Can anyone tell me how to emit a 3.2 micrometer(μm) wavelength with as much energy as possible? How could it be "homemade"? Is it possible?
Thank you so much

 

[berkeman]

Welcome to PF.

What is the application? How much power are we talking about here? It looks to be in the IR part of the EM spectrum, right?

http://www.pas.rochester.edu/~blackman/ast104/spectrum.html

 

[Vincent L]

Thank you for taking the time. My english is limited.
So i want it conceiled in a box. I want to reflect the emission so it can heat the molecules i put in the box as much it is possible.

 

[tech99]

Maybe the hot filament of a lamp. You can adjust the operating voltage so that IR is emitted without visible light. I use this to demonstrate the Greenhouse Effect, by altering the temperature to give long and short wavelength IR. At long wavelengths, radiation actually comes from the hot glass of the bulb, as the glass is opaque to long wavelengths.

 

[bob012345]

It seems to me you want a blackbody cavity with walls ~900K

 

[Vincent L]

Thank you all. I believe this to match with my questionning. I hope you all a good day

 

[Vincent L]

It seems to me you want a blackbody cavity with walls ~900K
View attachment 302326

Thank you!

 

[Vincent L]

Welcome to PF.

What is the application? How much power are we talking about here? It looks to be in the IR part of the EM spectrum, right?

View attachment 302246
http://www.pas.rochester.edu/~blackman/ast104/spectrum.html

Thank you

 

[Vincent L]

Maybe the hot filament of a lamp. You can adjust the operating voltage so that IR is emitted without visible light. I use this to demonstrate the Greenhouse Effect, by altering the temperature to give long and short wavelength IR. At long wavelengths, radiation actually comes from the hot glass of the bulb, as the glass is opaque to long wavelengths.

Thank you!

 

[sophiecentaur]

The problem is that the OP refers to a specific wavelength. All the above answers seem based on the assumption of a black body spectrum. If the OP were referring to spectral yellow wavelength or, say a millimetre radio wavelength, the answers would not have assumed thermal radiation.
What is it about a 3.2 micron wavelength that makes us assume that it's not monochromatic?
@Vincent L could you tell us about your choice of that particular wavelength and some more detail about your proposed experiment?

 

[Vincent L]

The problem is that the OP refers to a specific wavelength. All the above answers seem based on the assumption of a black body spectrum. If the OP were referring to spectral yellow wavelength or, say a millimetre radio wavelength, the answers would not have assumed thermal radiation.
What is it about a 3.2 micron wavelength that makes us assume that it's not monochromatic?
@Vincent L could you tell us about your choice of that particular wavelength and some more detail about your proposed experiment?

I want to CO2 to absorb it in ambient air, in a box. I want it to transfert heat to the other molecules. So I am taking the CO2 spectrum that is absorbed but not the rest Thank you for taking time

 

[berkeman]

I want to CO2 to absorb it in ambient air, in a box. I want it to transfert heat to the other molecules. So I am taking the CO2 spectrum that is absorbed but not the rest Thank you for taking time

Can you post a link to the $3.2 \mu m$ number that you posted? I'm finding different peaks for CO2 absorption specta...

 

[sophiecentaur]

Can you post a link to the 3.2μm number that you posted? I'm finding different peaks for CO2 absorption specta...

It seems to me that the OP is trying to measure the mechanism of the 'greenhouse effect'. Atmospheric absorption of IR is a very small effect, for a short path distance (i.e. a 'box'). It's pretty subtle even over the tens of km of the path through the atmosphere and many years of input power. If the effect were really that obvious we wouldn't be having difficulties with the climate change deniers.

@Vincent L 's idea is more of a thought experiment than one which would be practical. It would involve measuring a tiny temperature change, probably involving comparative readings for a box of CO2 and one with the equivalent mass of CO2-free air. A source of narrow band IR energy could be a filtered halogen or LED source, such as you can get for back pain relief. An IR photography floodlight wouldn't have the necessary power, although the spectrum could be better.

It's a good topic for discussion though and throws up a lot pf practical factors about this sort of measurement.