CSIP: PRELIMS BOOSTER SERIES -572 Science and Technology


Sound Amplification by Stimulated Emission of Radiation (SASER)


Scientists in China have developed a ground-breaking “sound laser” that emits particles of sound instead of light, making it the most powerful of its kind.


  • A SASER device utilizes an active medium through which sound waves travel. This medium can be a liquid with gas bubbles or a special material with specific properties.
  • An external source, like an electric field, acts as a pump to generate sound waves (vibrations) within the medium. These initial sound waves are called seed waves.
  • The active medium has unique properties that allow for stimulated emission of sound waves. Imagine a domino effect – when a seed wave interacts with certain particles in the medium, it stimulates them to emit their own sound waves.
  • These emitted waves are in phase (synchronized) with the seed wave, leading to amplification.


  • Due to stimulated emission, the sound waves gain coherence (similar to lasers) and  This translates to a highly directional and powerful sound beam emerging from the SASER.

Applications (potential):

  • Medical Imaging: High-resolution imaging techniques using sound waves.
  • Non-Destructive Testing: Inspecting materials for flaws without causing damage.
  • Underwater Communication: Long-range and high-fidelity communication through water.
  • Shock Wave Generation: Creating controlled shock waves for specific purposes.


  • Maintaining population inversion: The condition where more particles in the medium are excited to emit sound waves than those absorbing them.
  • Designing efficient pumping mechanisms.
  • Minimizing sound wave losses within the device.

Overall, SASER is a fascinating concept with the potential to revolutionize various fields that rely on powerful and focused sound. While there are hurdles to overcome, research in this area continues to make significant progress.