Question about TEM laser modes

[sopark4000]

Ok so I was looking through this picture of different TEM modes.

If you look at the pic TEM10 is basically just TEM01 rotated 90 degrees. The same goes for TEM02 and TEM20 as well as TEM12 and TEM21.

So what's the deal with this. What's the point. The only thing I can think of is that you aren't going to be turning gas lasers upside down or on there side etc. Any answers on this?

 

[Misanthrop]

Re: Question about TEM laser moded

I think it depends on the crystals operating temperature, my 473 does TEM01 when its just switched on and then TEM00 after a couple of minutes.

 

[ElektroFreak]

Re: Question about TEM laser moded

It's also relevant because of light polarity. Many lasers are polarized in one direction or another, and because of this there is a difference between the horizontal and vertical planes. When the laser is built, care is placed in the orientation of the internal components so that the polarization (if it exists at all) is perfectly vertical or horizontal. The modes of the laser are referenced against these planes also.

 

[sopark4000]

Re: Question about TEM laser moded

It's also relevant because of light polarity. Many lasers are polarized in one direction or another, and because of this there is a difference between the horizontal and vertical planes. When the laser is built, care is placed in the orientation of the internal components so that the polarization (if it exists at all) is perfectly vertical or horizontal. The modes of the laser are referenced against these planes also.

Ok this is making more sense to me now.