Is laser light polarized or unpolarized?

  • Context: Undergrad 
  • Thread starter Thread starter klng
  • Start date Start date
  • Tags Tags
    Laser Light
Click For Summary

Discussion Overview

The discussion centers around whether laser light is polarized or unpolarized, exploring the characteristics of laser light, including its coherence and frequency. Participants examine the conditions under which laser light may exhibit polarization and the factors influencing this property.

Discussion Character

  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants assert that laser light is polarized, particularly due to the use of a Brewster window, which can enhance polarization in certain types of lasers.
  • Others argue that not all laser light is polarized, highlighting that the presence of a resonator allows for mode competition that can result in unpolarized lasing.
  • It is noted that different types of lasers exhibit varying degrees of polarization, with gas lasers and Nd:YAGs being highly polarized, while diode lasers may be less so or even elliptically polarized.
  • A later reply emphasizes that the existence of multi-mode lasers means that unpolarized lasing is possible, and not all lasers utilize a Brewster window.

Areas of Agreement / Disagreement

Participants express differing views on the polarization of laser light, with some asserting it is generally polarized while others maintain that it can also be unpolarized. The discussion remains unresolved with multiple competing perspectives.

Contextual Notes

Participants reference specific types of lasers and their polarization characteristics, indicating that the discussion is influenced by the definitions and conditions under which lasers operate. There are unresolved aspects regarding the implications of mode competition and the role of resonators in determining polarization.

klng
Messages
22
Reaction score
0
Hi all,

I understand laser to be monochromatic (i.e. single frequency) and coherent (i.e. all the waves are in phase with each other.)

My question is : is laser a form of polarized light too? In other words, can the electric field be in almost all possible plane directions, or is it just limited to just one plane?

Pls advise. Thanks. Happy new year.
 
Science news on Phys.org
Laser light is polarized due to the use of a 'Brewster window' which acts as both mirror and output. Some laser light is more polarized than others- gas lasers and Nd:YAGs are highly (linearly) polarized, while diode lasers are much less and may even be elliptically polarized. VCSELs can have very non-classical states, like radial and tangential polarization.
 
  • Like
Likes   Reactions: genxium and TOTS
Thanks andy!
 
Hello,
It is a common mistake to think that laser light is always polarized, but this is not the case.
All lasers involve some kind of a resonator which causes a mode competition between different modes and also polarizations, in which the least lossy mode lases. In the same way that there exists multi-mode lasers, in which several spatial modes are lasing, there is generally no prohibition on unpolarized lasing.
Further more, not all lasers involve a Brewster window...
Please notice the following links:
http://www.opticsinfobase.org/abstract.cfm?uri=ASSP-2006-MB7
http://www.freepatentsonline.com/5075893.html

cheers!
 

Similar threads

  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 10 ·
Replies
10
Views
3K
Replies
10
Views
3K
  • · Replies 1 ·
Replies
1
Views
11K
  • · Replies 10 ·
Replies
10
Views
3K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 8 ·
Replies
8
Views
15K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 12 ·
Replies
12
Views
4K