A milliwatt-level cw laser source at 224 nm

Several new results are reported in singly ionized, hollow-cathode silver, copper, and gold vapor lasers. For the first time, a milliwatt-level cw laser source is demonstrated at 224 nm, with a threshold as low as 2 A. We have also extracted several hundred milliwatts of peak pulse power output at a number of wavelengths below 300 nm.