Certified Fiber Optics Practice Exam

In the process of stimulated emission, what is the relationship of the emitted photons?

1. They have different wavelengths

2. Each has the same energy

3. Each has the same phase relationship and direction

4. They are emitted randomly

The correct answer is: Each has the same phase relationship and direction

In the process of stimulated emission, the key characteristic of the emitted photons is that they all have the same phase relationship and direction. This phenomenon occurs when an excited atom or molecule is prompted to release a photon of light due to the influence of an incoming photon of the same energy. The crucial aspect of stimulated emission is that the emitted photon will match not only the energy of the incoming photon but also its phase and direction, resulting in coherent light. This coherence is fundamental to the operation of lasers, where the amplified light consists of photons that are in phase with one another, traveling in the same direction. This coherent nature leads to the unique properties of laser light, such as its focusability and ability to travel long distances without spreading out. In contrast, the other options do not accurately describe the relationship of the emitted photons during stimulated emission; they imply randomness or varying attributes that are not characteristic of the coherent process involved in this phenomenon.