What is the difference between active and passive q-switching?

There are a wide variety of q-switch technologies, but the technique as a whole can be broken down into two primary categories of q-switches, passive and active. Active q-switches could be a mechanical shutter device, an optical chopper wheel, or spinning mirror / prism inside the optical cavity, relying on a controllable, user set on/off ability. Passive q-switches use a saturable absorber, which can be a crystal (typically Cr:YAG), a passive semiconductor, or a special dye, and automatically produce pulses based on it’s design. Both passive and active q-switching techniques produce short pulses and high peak powers, but they each have their pros and cons. When choosing between actively q-switched and passively q-switched lasers, the key is to understand the tradeoffs between cost/size and triggering/energy and decide which is best for your particular application. Read more about these tradeoffs in this article: “The Advantages and Disadvantages of Passive vs Active Q-Switching.” Get more information from our Lasers 101, Blogs, Whitepapers, FAQs, and Press Release pages in our Knowledge Center!