Continuous-Wave and Mode-Locked Operation of an In-Band Pumped Tm,Ho,Lu:CaGdAlO[sub.4] Laser

• Published in: Applied sciences 2023-12, Vol.13 (23)
• Main Authors: Zeng, Huangjun, Xue, Wenze, Murray, Robert T, Chen, Weidong, Pan, Zhongben, Wang, Li, Cui, Chen, Loiko, Pavel, Mateos, Xavier, Griebner, Uwe, Petrov, Valentin
• Format: Article
• Language: English
• Subjects: Lasers
• ISSN: 2076-3417; 2076-3417
• DOI: 10.3390/app132312927

We investigate in-band pumping of a Tm,Ho,Lu:CaGdAlO[sub.4] laser using a Raman-shifted Er-fiber laser (1678 nm), in the continuous-wave (CW) and mode-locked (ML) regimes. A maximum output power of 524 mW is obtained in the CW regime with a 5% output coupler at an absorbed pump power of 2.04 W, corresponding to a slope efficiency of 27.9%. A maximum CW wavelength tuning range of 160 nm at the zero level, from 1984 to 2144 nm, is obtained with a 0.2% output coupler. In the ML regime, pumping with 5.5 W (unpolarized), the average output power (0.2% output coupler) reaches 148 mW at a repetition rate of ~96 MHz. The output spectrum is centered at 2071.5 nm with a FWHM of 21.5 nm (σ-polarization). The pulse duration amounts to 218 fs (time-bandwidth product equal to 0.327).