Lasers work by emitting controlled radiation, stimulating atoms to excite electrons and create controlled light. This light is a coherent beam of electromagnetic energy with all the waves reaching the same frequency and phase. However, some lasers produce a steady, continuous light, while others are pulsed. Read on to learn more about the difference between continuous lasers and pulsed lasers.
QCW vs. Pulse
You’ll encounter three types of lasers: continuous wave (CW), quasi-continuous wave (QCW), and pulse lasers. QCW lasers are also pulsed lasers, but their pulses are in the microsecond range, whereas true pulse lasers are in the nanosecond range and much narrower and faster. Generally, the shorter the pulse, the higher the instantaneous power the laser can achieve due to the reduced thermal effect. Laser diodes designed for pulsed applications can achieve higher peak power because their duration limits the heat buildup.
Laser Power
One of the main differences between CW lasers and pulsed lasers is their power output. Pulsed lasers can produce high peak power, while their average power is relatively low. By comparison, CW lasers produce continuous power. Because of these different power outputs, lasers have many diverse uses. Pulsed lasers are great for spot and seam welding or biological sample testing, where heat input is a significant factor, such as with medical devices and batteries. Alternatively, CW lasers are an excellent option for high-speed seam welding tasks like pressure sensors, airbag initiators, and battery tabs.
Calculating MPE
When working with lasers, safety equipment is one of the most important things you need. Precise radiation emissions stimulate the light of a laser, and you must protect yourself from this radiation. Calculating safety protections with a CW laser is easy since the power output is consistent. However, calculating the maximum permissible exposure (MPE) with a pulsed laser is much more difficult as the peak energies are difficult to calculate. You must consider factors like wavelength, energy per pulse, pulse width, and frequency. These calculations are necessary to ensure anyone working with the laser is as safe as possible.
Different Uses
As mentioned previously, with pulse lasers, you can have much higher power peaks than with CW lasers, which creates many opportunities. For example, CW lasers can work for extended periods, but depending on what you’re working with, this can develop heat-related problems and potentially even deform what you’re working with. Pulse lasers are great for avoiding these issues. Also, since they’re not continually operating, they’re great for cutting and marking without damaging the product, though they do require more maintenance and consumables.
The difference between continuous lasers and pulsed lasers is clear to see, but one is not better than the other. Instead, they have particular uses in different situations to obtain the best results possible. For your lasers to work correctly, whether continuous or pulsed, you must ensure you have the proper setup. At Arroyo Instruments, we have various laser equipment, including laser diode mounts, that you’ll need to keep your lasers functional and deliver the best results possible.
