Tunable and passively Q-switched laser operation of Tm:CaYAlO4 between 1848 nm and 1876 nm

Abstract

Abstract Laser emission between about 1850 and 1880\u202fnm is of great interest for neural stimulation applications. We report here on the diode-pumped, continuous-wave and passively Q-switched laser operation of Tm:CaYAlO4 in this specific wavelength domain, for the first time to our knowledge. In the continuous-wave regime, the maximum output power reaches 5.35\u202fW at 1864\u202fnm with a laser slope efficiency of about 40.5%. Using a Cr:ZnSe saturable absorber, passive Q-switching is achieved with a maximum average output power of 2.37\u202fW at 1857\u202fnm. The narrowest laser pulse width is found to be about 59\u202fns for a repetition rate of 35.3\u202fkHz and the corresponding laser pulse peak power and pulse energy are about 1.145\u202fkW and 67.5\u202fμJ, respectively. By introducing an undoped YAG crystal as intracavity etalon, tunable and passively Q-switched laser operation is obtained between 1848 and 1876\u202fnm while keeping high pulse energies and peak powers.