Researchers at Klastech (Dortmund, Germany) have developed the first continuous-wave (CW) all-solid-state ruby laser at 694.3 nm, with an output power of greater than 100 mW—the first step toward an efficient CW ultraviolet (UV) source at 347 nm through second-harmonic generation from the fundamental emission of the ruby source.
Unlike a conventional diode-pumped solid-state (DPSS) intracavity-frequency-doubled laser, in which the fundamental wavelength from a laser crystal is fed into a nonlinear crystal within the same cavity to produce a shorter wavelength, Klastech uses a double-enhanced intracavity-frequency-conversion (DENICAFC) technique that puts the nonlinear crystal inside its own cavity, impedance-matched with the active crystal in a patented three-mirror arrangement that multiplies the power level of the fundamental frequency interacting with the nonlinear crystal without upsetting the optimal lasing conditions for the laser active crystal. Because the efficiency with which the second harmonic is produced using DENICAFC is a factor of 10 better than any other method, shorter wavelengths such as CW 347 nm UV light can be generated without using the high-power pump lasers or pulsed technology needed when frequency tripling 1064 nm light, for example. Contact Fedor Karpushko at [email protected].