5†µm CW Ce3+-doped chalcogenide glass fiber laser with 17% slope efficiency.

Efficient room temperature mid-infrared laser action in a Ce3+-doped chalcogenide fiber was demonstrated. The fiber had a doped selenide glass core in an undoped sulfide glass cladding. The pump source was a CW Fe2+:ZnSe laser emitting at 4.14 µm. The optimized fiber length allowed obtaining up to 7 mW of 5.06 µm output with 17% slope efficiency at room temperature.

Resonantly pumped Ce3+ mid-infrared lasing in selenide glass.

In high purity Ce3+-doped selenide glass pumped by a 4.08 µm Fe:ZnSe laser, 5.1-5.5 µm laser oscillations were observed. This is the first evidence of laser action corresponding to the 2F7/2→2F5/2 transition of Ce3+ ions.

Efficient Fe:CdTe laser producing 0.35 J pulses in the 5 µm spectral range.

High-energy laser operation of a Fe2+-doped single-crystal CdTe is demonstrated at the temperature of 77 K. Pumped with 250 µs pulses of a 4.08 µm Fe:ZnSe laser, the Fe:CdTe laser produced a record output of 0.35 J, with a slope efficiency of 44%. A further up-scaling by employing high-energy pump sources is feasible, thus facilitating material-processing applications. The laser was tunable from 4.86 to 5.37 µm. In a nonselective cavity, the laser's central wavelength was 5.03 µm at 77 K, and shifted to 5.23 µm at 215 K. At the later operation point, reachable using a Peltier element, the laser still produced 0.15 J of output energy with an efficiency of 22%.

2 mJ room temperature Fe:CdTe laser tunable from 5.1 to 6.3 µm.

We report a room temperature (RT) operation of a Fe:CdTe laser pumped by a Q-switched 2.94 µm Er:Y3Al2(AlO4)3 laser. The Fe:CdTe laser produced 2 mJ of output energy at λ=5.55 µm with slope efficiency of 16% with respect to absorbed pump energy. With the use of an intracavity prism, the spectral tuning was demonstrated in the 5.1-6.3 µm range, being the longest wavelength tuning achieved for Fe2+:II-VI lasers. The lifetime of the upper laser level was measured to be 530 ns at RT.

Compact, highly efficient, 2.1-W continuous-wave mid-infrared Fe:ZnSe coherent source, pumped by an Er:ZBLAN fiber laser.

In this Letter, we report a compact and robust coherent source, operating in mid-infrared (IR) and based on the Fe:ZnSe chalcogenide gain medium, optically pumped by an Er:ZBLAN fiber laser. The output power of 2.1 W with a 59% slope efficiency with respect to the absorbed pump power at liquid nitrogen cooling is achieved. We show that strong re-absorption at a high pump power and iron ion doping concentrations leads to a continuous tuning of central wavelength from 4012 to 4198 nm. The robustness of a high-power Er:ZBLAN fiber laser combined with prominent spectroscopic properties of Fe:ZnSe media pave the way for the development of a reliable tunable continuous-wave mid-IR sources for scientific and industrial purposes.

Nanosecond-pulsed RT-operating at ~4 µm Fe:ZnSe laser pumped inside the cavity of a LD side-pumped Er:YLF laser.

Characteristics of an Fe:ZnSe laser with a new pump scheme were presented. An Fe:ZnSe crystal was placed inside the cavity of the Er:YLF laser pumped by a bar of laser diodes (LD) emitting at 975 nm. The high power 2.66 µm wave ~50 ns pulses were generated inside the cavity due to passive Q-switching of the Er:YLF laser by an Fe:ZnSe saturated absorber. These pulses pumped the Fe:ZnSe laser. As a result, the pulses with an energy of ~2 µJ at a wavelength around 4 µm and time duration of about 50 ns were generated. The laser operated in periodic-pulsed pump regime at room temperature with a repetition rate up to 200 Hz. The Q-switching pulse repetition rate during the pump pulse ran up to 2.5 kHz.

High-energy thermoelectrically cooled Fe:ZnSe laser tunable over 3.75-4.82 µm.

The characteristics of an Fe:ZnSe laser thermoelectrically cooled to 220 K are described. Output energy of 7.5 J and optical-to-optical efficiency of 30% have been demonstrated in single-shot operation at 4.3 µm with a 2.94 µm Er:YAG pump laser. By using an intracavity prism, continuous tuning from 3.75 to 4.82 µm has been obtained at output energy up to 3.1 J.

Continuous-wave broadly tunable high-power Cr:CdS laser.

We report spectroscopic characteristics and laser properties of the mid-infrared active laser medium Cr2+:CdS. Temperature-dependent absorption, luminescence and lifetime measurements of the 5E exited state allow determination of peak emission cross section value of 1.35 × 10-18 cm2 in σ-polarization at room temperature. Lifetime values vary from 7.6 µs at 8 K to 0.48 µs at 320 K, corresponding to 22 % quantum yield at 285 K. Under Tm-fiber laser pumping, the continuous-wave output reached 1.8 W at 2.5 µm with 35.5 % slope efficiency. With a single CaF2 prism, the CW Cr2+:CdS laser could be tuned from 2.240 to 3.285 µm.