>2 mJ @ 188 nm
Actinix has developed a hybrid fiber/solid-state laser system (Intensus DFB/OPA + Pulsed YAG + NLO) that generates millijoule scale light pulses in the vacuum ultraviolet at 188 nm. Pulse durations of <2ns and a temporal jitter less than 100ps are realized via a sum-frequency generation process where light at 1599nm is mixed with light at 213nm in non-linear crystals (LBO or CLBO). A wavelength-stabilized, seed pulse at 1599nm is derived from a pulse-modulated, single-frequency distributed feedback laser diode that is subsequently boosted to the micro-joule scale with erbium fiber L-band amplifiers. A two-stage optical parametric amplifier (OPA) is then utilized to increase the 1599nm pulse energy to greater than twenty millijoules. The main advantages of this approach over an OPO configuration are the low temporal jitter of the resulting amplified pulse and the preservation of the short pulse duration and narrow bandwidth of seed laser. The OPA first stage is a high-gain green pumped KTP crystal followed by an IR pumped second stage consisting of tandem KTP crystals. The 213nm light is generated as the fifth harmonic of the system pump laser.