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• A promising laser gain medium at 2.7 μm region, 7 at.% Er:Y 2 O 3 single crystal has been successfully grown. • The mid-infrared continuous-wave laser properties of 7 at.% Er:Y 2 O 3 crystal have been demonstrated for the first time. • By using saturable absorber, the pulsed laser at 2724 nm with the shortest pulse duration of 393 ns was achieved. As a promising laser gain medium at 2.7 μm region, 7 at.% Er:Y 2 O 3 single crystal has been successfully grown, but its laser properties have not yet been reported. Using Er:Y 2 O 3 crystals as laser gain medium means that the problem of optical diffraction loss in Er:Y 2 O 3 ceramics was avoided and higher quality laser can be obtained. On this basis, the continuous wave and passively Q-switched laser properties of this crystal have been demonstrated for the first time in this work. In continuous-wave operation, the maximum output power of 220 mW was obtained at 2725 nm. In the passively Q-switched operation, a 2724 nm laser was achieved with a shortest pulse duration of 393 ns. This is the first laser demonstration of the 7 at.% Er:Y 2 O 3 cubic crystal, and also is a vital step towards obtaining a higher quality mid-infrared laser. These laser characteristics also indicate great potential of Er:Y 2 O 3 crystal for the generation of mid-infrared lasers. [ABSTRACT FROM AUTHOR]

We demonstrated a passively Q-switched Er:Ca0.8Sr0.2F2 laser with indium tin oxide nanowire arrays as an optical modulator in the mid-infrared region. In the Q-switched regime, the maximum output power of 58 mW with a slope efficiency of 18.3% was acquired. Meanwhile, the minimum pulse duration and highest repetition rate of the stable pulse trains were 490 ns and 17.09 kHz, corresponding to single pulse energy of 3.4 μJ and peak power of 6.93 W, respectively. To the best of our knowledge it was the first time that indium tin oxide nanowire arrays were employed as a saturable absorber to make pulse lasers carried out at 2.8 μm. The experimental data show that indium tin oxide nanowire arrays can be employed as a competitive candidate for saturable absorber in the field of mid-infrared solid-state lasers. [ABSTRACT FROM AUTHOR]

• An actively Q-switched Er:CaF 2 -SrF 2 laser by a TeO 2 acousto-optic crystal was demonstrated. • The performance of Er:CaF 2 -SrF 2 actively Q-switched laser was studied for the first time. • These results exhibit potential application of high-energy mid-infrared laser devices for Er:CaF 2 -SrF 2 crystal. A diode-end-pumped Er:CaF 2 -SrF 2 laser actively Q-switched by a TeO 2 acousto-optic crystal was demonstrated for the first time, to our best knowledge. By setting the repetition rate of radio frequency signal, 2.73 μm Q-switched lasers with repetition rates of 100–1000 Hz were obtained. With 100 Hz repetition rate, a 390 μJ pulse energy and a 176 ns pulse duration were employed at an absorbed pump power of 2.17 W, and the corresponding peak power was 2.2 kW. These results prove that Er3+-doped CaF 2 –SrF 2 crystal is promising for actively Q-switched laser with high peak power in the mid-infrared region. [ABSTRACT FROM AUTHOR]

Er3+-doped CaF 2 single-crystal fibers (SCFs) were successfully grown using a modified temperature gradient technique (TGT) method. With a fiber-coupled 976 nm laser diode (LD) pump source and 4 at.% Er:CaF 2 SCF, mid-infrared region (MIR) laser operations were realized for the first time. A passively Q-switched (PQS) Er:CaF 2 SCF laser at 2.8 μm was demonstrated by using graphene saturable absorber (SA). Under an absorbed pump power of 1.52 W, a maximum output power of 220 mW was obtained with a pulse duration of 632.9 ns and a repetition rate of 59.41 kHz, corresponding single pulse energy and peak power are 3.70 μJ and 5.85 W, respectively. The dependence of the operational parameters on pump power was also investigated experimentally. We also found that the SCF possesses superior laser performance when compared with Er:CaF 2 bulk crystal. Those results implied SCF is a kind of promising laser gain mediums. • The 4 at.% Er3+-doped CaF 2 single-crystal fiber (SCF) was successfully grown. • The laser performance of Er:CaF 2 SCF has been demonstrated the first time. • Diode-pumped Er:CaF 2 SCF Q-switched lasers with graphene have been studied. • Compared with the Er:CaF 2 bulk crystal, SCF shows superior laser performance. [ABSTRACT FROM AUTHOR]

High-quality all-carbon nanostructure graphdiyne (GDY) saturable absorber was successfully fabricated and saturable absorption properties in the 2 μm region were characterized using a commercial mode-locked laser as a pulsed source. The fabricated GDY was first used as an optical switcher in a passively Q-switched Ho laser. Under absorbed pump power of 2.4 W, the maximum average output power and shortest pulse width were 443 mW and 1.38 µs, at a repetition rate of 29.72 kHz. The results suggest that GDY nanomaterial is a promising candidate as an optical modulator for generation of short pulses in Ho-doped lasers at 2.1 μm. [ABSTRACT FROM AUTHOR]

• The performance of diode-pumped (Nd3+-doped) Ca 0.7 La 0.3 Al 12 O 19 (Nd:CLA) lasers was studied for the first time. • By inserting a Cr4+:YAG absorber, we successfully achieved a passively Q-switched laser. • Comparation between a- and c-cut disordered Nd:CLA lasers were made. A new neodymium-doped (Nd3+-doped) Ca 0.7 La 0.3 Al 12 O 19 (Nd:CLA) disordered crystal was successfully grown by the Czochralski method. The performance of diode-pumped Nd:CLA (a-cut and c-cut) lasers was demonstrated for the first time. For the c-cut crystal continuous-wave (CW) operation, we obtained the highest output power of 2.08 W at the wavelength of 1053.2 nm, and the slope efficiency was 23% versus the incident pump power. By inserting a Cr4+:YAG absorber, we successfully achieved a passively Q-switched laser, and the shortest pulse width was 18.36 ns with a peak power of 364.6 W. Compared with a-cut crystal, c-cut crystal has superior laser characteristics. [ABSTRACT FROM AUTHOR]