A linearly polarized 1123 nm Nd:YAG laser using a Fabry–Perot filter as output mirror

We propose and demonstrate an 1123 nm Nd:YAG laser by exploiting a dielectric Fabry–Perot band-pass filter as laser output mirror. A fiber-pigtailed 808 nm laser diode array is used to pump an <111>-cut Nd:YAG crystal with a plano-plane resonator cavity. The dielectric Fabry–Perot filter as output mirror is specially designed to suppress the strong emission around 1064 nm and facilitate the oscillation of 1123 nm weak emission. A linearly polarized 1122.5 nm laser is achieved. The maximum output power of the laser is 105 mW and the slope conversion efficiency is 4.58% with the threshold pump power of 2.9 W. Passively Q-switched 1123 nm laser is realized using a [100]-cut Cr:YAG crystal as Q-switch. FWHM pulse width of 121 ns and pulse repetition rate of 2.3 kHz is achieved at pump power of 5.3 W. The design principle of the Fabry–Perot filter used as output mirror is discussed and the advantages of the method are summarized.