True CW 193.4-nm light generation based on frequency conversion of fiber amplifiers

We present a source of line-narrowed continuous-wave (CW) radiation at 193.4 nm with over 10 mW of output power for the first time, to our knowledge. The system configures four successive frequency conversions of outputs from three single-frequency fiber amplifiers at 1064, 1107, and 1963 nm. The 266-nm beam produced by frequency quadrupling of 1064-nm light is sum-frequency mixed with the 1963-nm light to generate 234.3-nm radiation, which is consequently mixed with the 1107-nm light to generate 193.4-nm radiation. Both mixings are achieved in temperature-tuned non-critically phase-matched (NCPM) crystals.