Tunable Pulsed Dysprosium Laser Within a Continuous Range of 545 nm Around 3 μm

We report a widely tunable pulsed dysprosium (Dy) -doped fluoride fiber laser within a 545 nm continuous wavelength range around 3 mu m, where a home-made random Raman fiber laser (RRFL) at 1.690 mu m acts as the pump, and a commercial InAs saturable absorber (SA) is adopted as the Q-switcher. The designed RRFL, excited by a 1.055 mu m ytterbium-doped fiber oscillator, can provide the 8(th) order Stokes emission at 1.690 mu m with a high spectral purity of 98.6% and a maximum output power of 14.4 W. Feeding it to a Dy cavity involving an InAs SA and a ruled diffraction grating in a Littrow configuration, stable Q-switching can be initiated and tuned within the continuous/total range of 2.775 similar to 3.320 mu m (545 nm)/2.765 similar to 3.338 mu m (573 nm), an extension of 50% over the prior 370 nm record [Opt. Lett., vol. 44, no. 9, pp. 2322-2325, 2019], representing the widest level to date from a pulsed rare-earth-doped laser at any wavelengths, to the best of our knowledge. When the wavelength is tuned to 2.992 mu m, a maximum average power of 106 mW with 460 ns pulse width, 125 kHz repetition rate, and 0.85 mu J pulse energy is achieved. This work marks the first pulsed Dy-doped fluoride fiber laser pumped at similar to 1.7 mu m while exhibiting the utility of InAs in pulse generation at the wavelengths of 3 similar to 3.4 mu m for the first time, to the best of our knowledge. The demonstration highlights the great potential of similar to 1.7 mu m pumped Dy-doped fluoride fiber laser as a platform for developing widely tunable pulsed sources in the 3 mu m region of the mid-infrared.

Automated summary

This paper reports a widely tunable pulsed dysprosium-doped fluoride fiber laser with a continuous wavelength range of 545 nm in the mid-infrared region of 3 μm. This work demonstrates the potential of this laser as a platform for developing widely tunable pulsed sources in the mid-infrared region.