A cavity laser refers to the specific space within a laser system where light is confined and amplified to produce a laser beam. This space, often called the laser cavity or optical resonator, plays a crucial role in the lasing process.
Understanding the Laser Cavity
The cavity, which can be formed by mirrors or other reflective surfaces, provides the necessary feedback for photons. These photons bounce back and forth within the cavity, stimulating further emission of light from the gain medium. This process is crucial for the laser to operate effectively.
Key Functions of a Cavity
- Photon Feedback: The cavity's reflectivity is essential for providing photon feedback. This means that light emitted within the cavity is reflected back into the gain medium, stimulating further emission and building up a stronger light field.
- Mode Selection: The cavity geometry determines the lasing modes (specific light patterns) that can exist. Different cavity designs lead to different laser output characteristics.
- Coherent Light Extraction: The cavity also determines how efficiently the coherent light produced is extracted from the laser system. The reflectivity of the mirrors influences how much light remains within the cavity versus how much is emitted as the laser output.
Example: Nanowire Laser Cavity
As referenced, in the case of a nanowire laser, the nanowire itself encloses the laser cavity. The reflectivity of the nanowire's ends governs the photon feedback and the efficiency of light extraction. In this micro-scale system, precise control of the cavity's physical characteristics is crucial for achieving desired lasing properties.
| Feature | Description |
|---|---|
| Definition | Space within the laser where light is confined and amplified. |
| Function | Provides photon feedback, selects lasing modes, enables light extraction. |
| Reflectivity | Determines feedback strength and light output efficiency. |
| Example | In a nanowire laser, the nanowire itself forms the cavity. |
In conclusion, a cavity laser refers to a system where a laser's cavity is central to its operation, dictating the modes, feedback mechanisms, and extraction efficiency of coherent light.
