Several microwatts of tunable cw radiation near 194 nm in a linewidth of less than 2 MHz have been generated by sum-frequency mixing the radiation from a frequency-doubled argon-ion laser with the radiation from a ring dye laser in a crystal of potassium pentaborate. An external ring cavity resonant with the dye laser gives an enhancement factor of about 14 in the sum-frequency-generated radiation power. The Doppler-limited absorption spectrum of the 6s2S1/2–6p2P1/2 first resonance line of natural Hg ii has been resolved, and the vacuum wave number for the mass-202 isotope has been measured to be 51485.904(20) cm−1.
© 1983 Optical Society of America
Original Manuscript: November 4, 1982
Published: February 1, 1983
H. Hemmati, J. C. Bergquist, and Wayne M. Itano, "Generation of continuous-wave 194-nm radiation by sum-frequency mixing in an external ring cavity," Opt. Lett. 8, 73-75 (1983)