Maximizing Laser Focus: Understanding Divergence and Distance Limitations

  • Context: Undergrad 
  • Thread starter Thread starter easyrider
  • Start date Start date
  • Tags Tags
    Focus Laser
Click For Summary

Discussion Overview

The discussion centers on the limitations of laser focus, particularly regarding divergence and the potential distance over which lasers can be effectively focused. Participants explore theoretical aspects, practical applications, and challenges related to laser technology in various contexts, including deep-space communication.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • One participant asserts that lasers experience divergence due to diffraction, questioning whether this divergence occurs after the point of focus and if there is a limit to how far a laser can be focused.
  • Another participant introduces Gaussian beams, mentioning the importance of the beam waist and divergence angle, and references the Rayleigh length as a significant derived quantity.
  • A participant speculates that with a sufficiently large aperture and appropriate optics, it may be possible to focus a laser over distances of 1 or 2 light-seconds, questioning if there are limits to this capability.
  • Discussion includes references to deep-space communication systems, such as NASA's LCRD and LADEE experiments, and ESA's LISA mission, highlighting their use of lasers and the complexities introduced by atmospheric turbulence and scattering in long-distance applications.
  • One participant requests clarification on the use of lasers in maintaining fixed configurations for satellite systems, indicating an interest in more detailed information and acknowledging the effects of atmospheric conditions while focusing on vacuum scenarios.

Areas of Agreement / Disagreement

Participants express a range of views regarding the limitations of laser focus and the impact of atmospheric conditions, indicating that multiple competing perspectives exist without a clear consensus on the extent of laser focusing capabilities.

Contextual Notes

Participants note the complexities introduced by atmospheric turbulence and scattering, particularly in long-distance laser systems, while some discussions focus on theoretical considerations in a vacuum, highlighting the dependence on specific conditions and definitions.

Who May Find This Useful

Individuals interested in laser technology, deep-space communication, and the theoretical aspects of beam divergence and focusing may find this discussion relevant.

easyrider
Messages
89
Reaction score
0
I know that lasers will always have divergence due to diffraction. With that said, they don't diverge until after the point of focus, correct? Is there a limit to how far a laser can be focused?
 
Science news on Phys.org
Thanks for your reply. If one has a big enough aperture and the right optics, you could focus it out to 1 or 2 light-seconds couldn't you? Is there a limit to how far off a laser can be focused?
 
There has been some work on deep-space communication systems (NASA's LCRD and LADEE experiments), and AFAIK there's a multi-satellite design by ESA that uses lasers to remain in a fixed configuration for gravitational wave detection (LISA)- not sure what stage in development they are, tho.

Note that atmospheric turbulence/scattering makes long distance laser systems (Boeing's airborne laser system, for example) hugely complicated- the THEL (Nautilus) system was shelved.
 
Andy Resnick said:
There has been some work on deep-space communication systems (NASA's LCRD and LADEE experiments), and AFAIK there's a multi-satellite design by ESA that uses lasers to remain in a fixed configuration for gravitational wave detection (LISA)- not sure what stage in development they are, tho.

Note that atmospheric turbulence/scattering makes long distance laser systems (Boeing's airborne laser system, for example) hugely complicated- the THEL (Nautilus) system was shelved.

Hm, please elaborate. What do you mean by uses lasers to remain in a fixed configuration? Dyou have a link/site with more info? Also, yes I am aware of atmospheric effects on the beam, I meant strictly in a vacuum.
 

Similar threads

Undergrad Using Diffraction (i.e., Fresnel Zone Plate) to defocus/diverge light
  • · Replies 2 ·
Replies
2
Views
2K
Undergrad What happens if I place light sources on the plane perpendicular to the principle axis of cylindrical lens?
  • · Replies 1 ·
Replies
1
Views
2K
Graduate The coherence length is much longer than the manufacturer claims
  • · Replies 10 ·
Replies
10
Views
3K
Graduate Moon Experiment: Laser Beam & Telescope for New Moon Phase
  • · Replies 17 ·
Replies
17
Views
4K
High School Poisson Spot Madness: Laser & Coin Lens Experiment
  • · Replies 5 ·
Replies
5
Views
2K
Graduate How to get a 30um (micrometer) laser diameter?
  • · Replies 3 ·
Replies
3
Views
2K
Undergrad Lens Calculations to Focus Light
  • · Replies 10 ·
Replies
10
Views
4K
Graduate Smallest diameter collimated laser/optical beam?
  • · Replies 1 ·
Replies
1
Views
4K
Undergrad Why is a laser's focus limited by diffraction?
  • · Replies 2 ·
Replies
2
Views
2K
High School Multimode optical fiber, physics beginner help :D
  • · Replies 37 ·
2
Replies
37
Views
5K