Can a circularly Polarized Laser impart momentum to air?

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SUMMARY

A circularly polarized laser beam, such as a 1-watt visible wavelength laser, does not impart linear or rotational momentum to air molecules, specifically nitrogen (N2) and oxygen (O2). The lack of absorption of visible light by air means that these molecules do not experience any momentum transfer. Additionally, ro-vibrational transitions in N2 and O2 are forbidden, and without a permanent dipole moment, air remains transparent to microwave radiation. Inducing electronic transitions in the ultraviolet (UV) spectrum is necessary for any rotational effects.

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  • Understanding of circular polarization in laser beams
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Pet Scan
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Does a circularly polarized laser beam, (say, 1 watt or so at visible wavelengths), impart linear or rotational momentum to air molecules.??
I'm not talking of ionization of air...which I know it doesn't, ...but rather momentum, in particular due to its Left or right CIRCULAR polarization.
Thanks.
 
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Pet Scan said:
Does a circularly polarized laser beam, (say, 1 watt or so at visible wavelengths), impart linear or rotational momentum to air molecules.??
I don't know what an air molecule is, so I will assume you are considering nitrogen and oxygen. Visible light is not absorbed by air, so the answer is definitely no. Ro-vibrational transitions in N2 and O2 are also forbidden, so even IR will not get significantly absorbed. Since they have no permanent dipole moment, air is also pretty much transparent to microwave radiation also. You would need to induce electronic transitions (in the UV) to get those molecules to rotate.
 
DrClaude said:
I don't know what an air molecule is, so I will assume you are considering nitrogen and oxygen. Visible light is not absorbed by air, so the answer is definitely no. Ro-vibrational transitions in N2 and O2 are also forbidden, so even IR will not get significantly absorbed. Since they have no permanent dipole moment, air is also pretty much transparent to microwave radiation also. You would need to induce electronic transitions (in the UV) to get those molecules to rotate.

Thanks for the explanation Dr.Claude...
 

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