What is the significance of having coherent light in a laser?

[Jye]

I understand that stimulated emissions produce coherent photons. What happens as a result of their coherence? My guess is that the laser beam does not spread out as much allowing it to travel further. Also, what is the property of a laser that allows the beam to travel great distances?

 

[berkeman]

I understand that stimulated emissions produce coherent photons. What happens as a result of their coherence? My guess is that the laser beam does not spread out as much allowing it to travel further. Also, what is the property of a laser that allows the beam to travel great distances?

Welcome to the PF.

Can you try Hyperphysics or Wikipedia to read a bit more about lasers? You may find the answer there. After you have read some more about lasers, post here to tell us what you have learned, and you will be able to ask a much more specific question after doing that reading.

 

[Jye]

The laser beam is highly collimated as the mirrors in the laser are perpendicular. Therefore only diverges minimally. Is this what allows the laser to travel great distances?

If a laser beam is coherent does this mean that all the photons in the front of beam strike a surface at the same time?

 

[Jye]

Am I correct?

 

[Nickie]

The significance of having coherent light in a laser is that it allows for the production of a highly focused and intense beam of light. This is because stimulated emissions produce photons that are all in phase with each other, meaning they have the same wavelength and direction of travel.

As a result of their coherence, the laser beam does not spread out as much, allowing it to maintain its intensity and direction over long distances. This is known as the principle of collimation and is a key property of lasers.

The property of a laser that allows the beam to travel great distances is its ability to maintain coherence over long distances. This is achieved through the use of mirrors and amplification of the light within the laser cavity, which helps to maintain the uniformity of the light waves.

In addition to allowing for long-distance travel, the coherence of laser light also allows for precise control and manipulation of the beam, making it useful in a wide range of applications such as cutting, welding, and telecommunications.