What factors affect the wavelength of laser?

What factors affect the wavelength of laser?

The wavelength of laser is not determined by a single factor, but is jointly determined by its core physical mechanism (stimulated radiation) and specific structural design. The core depends on the energy level structure of the working substance, and is also assisted and regulated by factors such as the resonant cavity and the pumping method.

The following factors can affect the wavelength of a laser:

Lasers are based on various laser media, such as gases, solids, semiconductors or doped optical fibers. Each laser medium has unique characteristics, which can affect its possible emission wavelength.

2. The gain medium is the active substance that generates stimulated radiation within the laser system. The characteristics of the gain medium (such as energy levels, electronic transitions and band gaps) determine the wavelength range that can be amplified.

3. The function of the pump source is to provide initial energy for the gain medium to initiate the laser generation process. The wavelength of the pump source will affect the excitation state and energy level of the gain medium, and thus have an impact on the emission wavelength.

4. Some lasers are equipped with tuning mechanisms that can adjust the output wavelength, thereby changing the emission wavelength within a specific range.

5. The design of the laser resonator (including mirrors and other optical components) will affect the selection of wavelength by changing the resonance mode and phase interference conditions.

6. Nonlinear optical effects (such as frequency doubling, sum or difference generation, and parametric processes) may generate harmonics or produce new wavelengths that the laser medium cannot directly generate.

7. Factors such as temperature and pressure can also affect the laser wavelength, which is particularly evident in gas lasers. The thermal effect on the gain medium may cause a shift in the emission wavelength.

In short, “determining the range of working substances, setting specific values for the resonant cavity, and ensuring output under excitation conditions” jointly determine the final output wavelength of laser.