A stable 2 W continuous-wave 261.5 nm laser for cooling and trapping\n aluminum monochloride

Abstract

We present a high-power tunable deep-ultraviolet (DUV) laser that uses two\nconsecutive cavity enhanced doubling stages with LBO and CLBO crystals to\nproduce the fourth harmonic of an amplified homebuilt external cavity diode\nlaser. The system generates up to 2.75 W of 261.5 nm laser light with a ~2 W\nstable steady-state output power and performs second harmonic generation in a\nlargely unexplored high intensity regime in CLBO for continuous wave DUV light.\nWe use this laser to perform fluorescence spectroscopy on the\n$X^1\\Sigma\\leftarrow A^1\\Pi$ transition in a cold, slow beam of AlCl molecules\nand probe the $A^{1} \\Pi|v'=0,~J'=1>$ state hyperfine structure for future\nlaser cooling and trapping experiments. This work demonstrates that the\nproduction of tunable, watt-level DUV lasers is becoming routine for a variety\nof wavelength-specific applications in atomic, molecular and optical physics.\n