Fluorescence of a laser vs its pulse duration

Click For Summary
SUMMARY

The discussion centers on the relationship between fluorescence lifetime and pulse duration in pulsed nitrogen lasers. It is established that the upper-state lifetime exceeds the pulse duration, enabling energy storage in the gain medium before lasing occurs. A population inversion is essential for effective lasing, where stimulated emission is favored over absorption. The rapid depletion of the upper state during lasing contrasts with the slower, random occurrences of fluorescence prior to this process.

PREREQUISITES
  • Understanding of pulsed laser operation
  • Knowledge of fluorescence and stimulated emission
  • Familiarity with population inversion concepts
  • Basic principles of gain media in lasers
NEXT STEPS
  • Research the principles of nitrogen laser operation
  • Learn about the mechanisms of fluorescence lifetime
  • Explore the concept of population inversion in laser physics
  • Investigate the role of gain media in energy storage for lasers
USEFUL FOR

Laser physicists, optical engineers, and researchers in photonics who are interested in the dynamics of pulsed lasers and fluorescence phenomena.

TheSearch
Messages
1
Reaction score
0
When working with a pulsed laser (nitrogen),
How can the fluorescence lifetime be longer than the pulse of the laser?

Thanks for any explanations
 
Science news on Phys.org
The upper-state lifetime is always longer than the pulse in pulsed lasers. This allows you to store energy in the gain medium prior to lasing. In a laser you must be able to create a population inversion, where a photon interaction (of the correct type) is more likely to stimulate emission than be absorbed. i.e. more energy available in upper to lower state transition than vice-versa. This requires some "storage time" in the upper state.

The pulse is short because of stimulated emission. The large quantity of photons cause the upper-state to be depleted quickly during lasing. Prior to that the fluorescence (spontaneous emission) happens more slowly at more random times.

https://eng.libretexts.org/Bookshel...on,_Spontaneous_Emission,_Stimulated_Emission
 
  • Like
Likes   Reactions: sophiecentaur and TheSearch

Similar threads

  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 2 ·
Replies
2
Views
10K
  • · Replies 5 ·
Replies
5
Views
8K
  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 8 ·
Replies
8
Views
3K
  • · Replies 10 ·
Replies
10
Views
3K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 13 ·
Replies
13
Views
3K