Different types of lasers use various methods to control output power based on their working principles, control mechanisms, and application requirements.
- adjusting the pump power
- duty cycle modulation
- change the intensity of dye or chemical
Here’s a summary of how some common continuous-wave lasers regulate their output power:
- CO₂ Lasers
CO₂ lasers, especially when operating in quasi-continuous or pulsed modes, often use duty cycle modulation to control the average output power. However, in continuous-wave (CW) mode, power can also be adjusted by controlling the pump current or excitation power (such as discharge current).
- Fiber Lasers
In continuous-wave (CW) mode, fiber lasers usually control output power by adjusting the pump power rather than the duty cycle. The more energy supplied by the pump source, the more the gain medium is excited, resulting in higher output power. Even in CW mode, adjusting pump power is the primary method of power control.
- Solid-State Lasers
Solid-state lasers (such as DPSS lasers) in CW mode typically control output power by adjusting the power of the pump source (usually lamp-pumped or diode-pumped), rather than by modulating the duty cycle. The pump power affects the gain of the laser medium, which in turn alters the output power.
- Semiconductor Lasers
Semiconductor lasers in CW mode typically adjust output power by varying the input current. Since the optical power of a semiconductor laser is proportional to the injected current, current modulation is a common way to control output power. While pulse modulation can be used for power adjustment, current control is more common for CW operation.
- Dye Lasers
Dye lasers typically adjust output power by changing the intensity of the pump source. Since the dye medium absorbs pump light to generate laser emission, adjusting the pump light’s intensity (or energy) is the primary method for controlling output power.
- Chemical Lasers
Chemical lasers produce laser output via chemical reactions, and their power output is typically controlled by adjusting the speed or intensity of these reactions. Thus, they do not rely on duty cycle modulation for power control but instead adjust the reaction conditions to regulate output power.
