What describes the Optical Cavity's role?

What describes the Optical Cavity's role?

• A. Acts like a resonant feedback system that focuses and amplifies the photon energy into a coherent beam
• B. It is the main energy source
• C. It determines polarization
• D. It emits electrons

Answer: (A)

The optical cavity acts as a resonant feedback loop that returns photons into the gain medium, causing them to build up and reinforce specific optical modes. By reflecting light back and forth between mirrors, it increases photon density and helps convert spontaneous emission into a coherent, directed beam. This feedback is what shapes the beam’s coherence and mode structure. The energy that actually powers the light comes from the pump energy driving the gain medium, not from the cavity itself. Polarization isn’t set by the cavity alone, and it doesn’t emit electrons.

The optical cavity acts as a resonant feedback loop that returns photons into the gain medium, causing them to build up and reinforce specific optical modes. By reflecting light back and forth between mirrors, it increases photon density and helps convert spontaneous emission into a coherent, directed beam. This feedback is what shapes the beam’s coherence and mode structure. The energy that actually powers the light comes from the pump energy driving the gain medium, not from the cavity itself. Polarization isn’t set by the cavity alone, and it doesn’t emit electrons.