Continuous-wave Ho Research Articles

A ring ZnGeP2 optical parametric oscillator pumped by a Ho:LuAG laser

We have demonstrated that we believe to be the first ring ZnGeP2 (ZGP) optical parametric oscillator (OPO) pumped by a pulsed Ho:LuAG laser. The maximum output power of the ring ZGP OPO laser was 5.51 W at 13.1 W incident Ho pump power, corresponding to a slope efficiency of 59.0 %. The ZGP OPO laser produced 14 ns mid-infrared pulses in the 3.72–4.01 and 4.37–4.75 μm spectral regions simultaneously. In addition, the continuous wave Ho:LuAG laser generated 26.5 W of linearly output at 2,094.4 nm at the absorbed Tm pump power of 49.9 W.

Continuous-wave Ho:GdVO4 laser pumped by Tm-doped fiber laser with a fiber Bragg grating at room temperature

We reported the Ho:GdVO4 laser pumped by Tm-doped laser with a fiber Bragg grating. 2.03W continuous-wave Ho:GdVO4 laser output power is obtained under 10.5W incident pump power, with the optical-to-optical conversion efficiency and slope efficiency of 19.3% and 32.3%, respectively, at 7°C. We can see that, the lower the temperature is, the better the laser output character is. The beam quality factor is M2∼1.29 measured by the traveling knife-edge method.

A narrow-linewidth continuous wave Ho:YALO3 laser with Fabry—Perot etalons

A narrow linewidth continuous wave Ho:YAP laser with two Fabry—Perot etalons pumped by a Tm:YLF laser is reported. The maximum output power reaches 8.3 W when the incident pump power is 15.8 W, with 52.5% optical-to-optical conversion efficiency and 62.6% slope efficiency. A stable laser output at 2118.1 nm is achieved, with a linewidth less than 0.4 nm (full width at half maximum). The beam quality factor is M2 ∼ 1.25, measured by the traveling knife-edge method.

The output characteristics of double-end-pumped Ho:LuAG laser at room temperature

Continuous-wave (CW) and Q-switched operation of a room-temperature Ho:LuAG laser was resonantly double-end-pumped by a diode-pumped Tm:YLF laser at 1.91 μm. The CW Ho: LuAG laser generated 24.5 W of linearly output at 2094.4 nm with beam quality factor of M 2 = 1.11 ± 0.02 for an absorbed pump power of 44.0 W, corresponding to optical-to-optical conversion efficiency of 55.7% and slope efficiency of 60.5%. Under Q-switched operation, a maximum output power of 24.1 W with a slope efficiency of 58.1% at 12 kHz was obtained. Also, the minimum pulse width of 32 ns was achieved, corresponding to the peak power was 37.7 kW.

A narrow linewidth continuous wave Ho:YAP laser with a volume Bragg grating

We report a diode-pumped CW Ho:YAP laser at room temperature with a volume Bragg grating (VBG) instead of the conventional mirror. The Ho:YAP laser operated at 2117.9 nm, with output power 8.1 W. The optical-to-optical conversion efficiency is 51.9% and slope efficiency is 61.1%. Also, a stable output and a narrow line width less than 0.3 nm FWHM are achieved. This is the first time to report a Ho:YAP laser with a volume Bragg grating.

Continuous wave operation of singly-doped Ho:LSO laser at room temperature

We present the room-temperature continuous-wave Ho:LSO laser single-pass-end-pumped by a diode-pumped Tm:YLF laser at 1.91 μm in this paper. Under different output couplers of 2.4, 5.0, and 14.0%, the laser output power and output spectrum of Ho:LSO laser operating at room temperature are investigated. The output wavelength of Ho:LSO laser was centered at 2106.5 nm with linewidth (FWHM) of about 3.2 nm. With T = 5.0%, the maximum output power of 2.4 W was achieved under the absorbed pump power of 11.1 W, corresponding to a slope efficiency of 38.0%.

Q-switched operation of an in-band-pumped Ho:LuAG laser with kilohertz pulse repetition frequency

We report continuous-wave (CW) and repetitively Q-switched operation of an in-band-pumped Ho:LuAG laser at room temperature. End-pumped by a Tm:YLF solid-state laser with emission wavelength of 1.91 μm, the CW Ho:LuAG laser generated 5.4-W output at 2100.7 nm with beam quality factor of M2∼1.03 for an incident pump power of 14.1 W, corresponding to slope efficiency of 67% with respect to absorbed pump power. Up to 1.5-mJ energy per pulse at pulse repetition frequency (PRF) of 3 kHz and 4.5-W average power with FWHM pulse width of 28 ns at 5 kHz were demonstrated in repetitively Q-switched operation.

A Continuous-Wave Ho:YAlO3 Laser with Output 8.5 W Pumped by a 1.91 μm Laser at Room Temperature

A cw high efficient Ho:YAlO3 laser pumped by 1.91 μm diode-pumped Tm:YLF laser at room temperature is realized. The maximum output power reaches 8.5W when the incident pump power is 15.6 W. The slope efficiency is 63.7%, and the Tm:YLF to Ho:YAP optical conversion efficiency is 54.5%. The laser wavelength is 2118.3 nm when the transmission of output coupler is 30%. The beam quality factor is M2 ∼1.39 measured by the traveling knife-edge method.

Continuous-wave and Q-switched operation of a resonantly pumped Ho:YAlO_3 laser

We demonstrated continuous-wave (CW) and Q-switched operation of a room-temperature Ho:YAlO(3) laser that is resonantly end-pumped by a diode-pumped Tm:YLF laser at 1.91 microm. The CW Ho:YAlO(3) laser generated 5.5 W of linearly polarized (EII c ) output at 2118 nm with beam quality factor of M(2) approximately 1.1 for an incident pump power of 13.8 W, corresponding to optical-to-optical conversion efficiency of 40%. Up to 1- mJ energy per pulse at pulse repetition frequency (PRF) of 5 kHz, and the maximum average power of 5.3-W with FWHM pulse duration of 30.5 ns at 20 kHz were achieved in Q-switched mode.

High Efficient Continuous-Wave Ho:YAG Laser Pumped by a Diode-pumped Tm:YLF Laser at Room Temperature

We present a high efficient continuous wave Ho:YAG laser pumped by a diode-pumped Tm:YLF laser with a Fabry–Perot etalon tuning at 1.91 μm. The maximum output power reaches 7.2 W when the absorbed pump power is 10.8 W. The slope efficiency (relative to the absorbed power) is 74.1%, and the Tm:YLF to Ho:YAG optical conversion efficiency of 60%, then the diode-to-Holmium optical conversion efficiency achieved is 21.0%. The wavelength is 2090 nm when the transmission of output coupler is larger than 20%. The beam quality factor is M2 ∼ 1.15 measured by the travelling knife-edge method.