Pulsars are a nickname given to pulsed lasers that emit a train of millisecond duration pulses as a single shot. These pulses allow for higher energy densities within each pulse and the time between allows for vaporized materials to disperse sufficiently to allow the next lance of purifying light to pierce the ejecta and cause successive explosions.
Pulsars are capable of operating in any wavelength from infrared to UV-C, but they often require wavelengths in the visible spectrum to achieve reasonable ranges in atmosphere. This primarily relegated them to use as military weapons; their IR-restricted counterparts had difficulties matching the range of ballistic weapons. However, it was discovered that pulsars are naturally suited to underwater use in the blue-green wavelengths. While a blinding risk, this has earned them a permanent niche as underwater cutting torches, and rarely as underwater weapons.
Like other lasers, shorter wavelength beams tend to excel in vacuum environments where there is no risk of atmospheric attenuation or absorption. In such environments, UV pulsars can achieve very long ranges, as compared to longer wavelength pulsars. Such lasers, however, still risk blinding despite not being visible to the naked eye - a fact that makes the risk that much greater. Consequently, such pulsars are relegated to the military sector by almost all governments.
Today, pulsars have been almost entirely replaced by the longer-ranged, more power Blasters. Despite this, pulsars can still be found occasionally as cheap civilian self-defense weapons where allowed by governments, and as primary weapons in militaries and militias too poor to afford modern blasters. Such military organizations are typically on the fringes of human space or in the poor systems that often serve as proxies in the struggles of larger galactic powers.