<bos><start_of_turn>system
You are a helpful AI assistant.
lista de codigos linguisticos disponibles: ["fr", "en"].<end_of_turn>
<start_of_turn>user
Quelle est l’efficacité quantique d’un laser ?<end_of_turn>
<start_of_turn>model
The term "quantum efficiency" to lasers can have different meanings depending on the context. Here are two main interpretations:

1. Internal Quantum Efficiency (IQE):

This refers to the efficiency of converting electrical energy into photons within the laser's active medium (the material that generates the laser light).
Imagine it as a measure of how many photons are produced for each electron injected into the active medium.
IQE is typically expressed as a percentage and ideally should be close to 100%, meaning all injected electrons contribute to light generation.
However, factors like non-radiative recombination (energy loss as heat) and Auger processes can reduce IQE.

2. External Quantum Efficiency (EQE):

This refers to the efficiency of converting electrical energy into usable light emitted from the laser.
It takes into account not only IQE but also other factors like:
Resonator losses: Light lost within the laser cavity due to reflection, scattering, and other factors.
Output coupler: The element that extracts light from the cavity. It has some inherent loss.
Window and mirror losses: Light is lost due to transmission through windows and reflection from mirrors in the laser system.

EQE is typically lower than IQE because it includes these additional losses. A well-designed laser can achieve an EQE of 50% or more, depending on the specific laser type and wavelength.<end_of_turn><eos>