Saturable Output Coupler Research Articles

High efficiency nanosecond passively Q-switched 23 µm Tm:YLF laser using a ReSe2-based saturable output coupler

A 785 nm diode-pumped nanosecond passively Q-switched (PQS) 2.3 µm Tm:YLF laser using a ReSe2-based saturable output coupler (SOC) was reported for the first time. The SOC combined the function of a passive Q-switch and output coupler, greatly reducing the additional insertion loss compared with a conventional separate structure. The modulation depth, saturation intensity, and nonsaturable loss for this ReSe2-based SOC were determined to be 1.3%, 1.7 GW/cm2, and 0.2%, respectively. A maximum average output power of 486 mw, a shortest pulse width of 716 ns, and a repetition rate of 5.0 kHz were obtained under the absorbed pump power of 7.21 W. The nanosecond pulses make the diode-pumped compact 2.3 µm thulium solid-state lasers more attractive for practical applications.

5.9 GHz graphene based q-switched modelocked mid-infrared monolithic waveguide laser.

A high repetition rate Q-switched modelocked ~2.1 µm monolithic waveguide laser is reported. Ultrafast laser inscription is used to fabricate 3D depressed cladding channel waveguides in holmium doped yttrium aluminium garnet. This results in a transversely single mode waveguide laser. With the use of a graphene based saturable output coupler, Q-switched modelocking was achieved with a pulse repetition frequency of 5.9 GHz and up to 170 mW of average output power. This first demonstration of multi-GHz repetition rate operation from a Ho3+:YAG laser provides a compact and convenient source for a number of applications.

Laser diode-pumped low timing jitter saturable output coupler Q-switched microchip laser: simulations and experiments

We studied the pulsed laser diode (LD)-pumped saturable output coupler (SOC) passively Q-switched Nd:YVO4 transmission microchip laser both numerically and experimentally. We demonstrated numerically that the timing jitter decreased with increasing pump power both in the continuous wave (CW) LD pump scheme and the pulsed LD pump scheme. Compared with the CW pump scheme, the pulsed LD pump scheme showed a better performance in timing jitter control due to the much higher peak power and shorter duration of the pulses. Experiments were also carried out to verify the theoretical analysis results. As the pump power of the CW LD increased, the timing jitter value of our laser decreased from 1.68% at 30 mW pump power to a constant around 0.86% at 90 mW. The output frequency can be controlled by changing the pump spot size in the rectangular shape pulsed pump scheme, and it was achieved from 333.3 to 71.4 kHz, while the relative timing jitter decreased from 0.10% to 0.03% accordingly. Additionally, the microchip laser had a good stability of output power, and the power fluctuation was below 2% in a 2-h measurement.

VBG-locked continuous-wave and passively Q-switched Tm:Y_2O_3 ceramic laser at 21 μm

A continuous-wave (CW) and passively Q-switched Tm:Y2O3 ceramic laser emitting at 2.1 μm were reported for the first time. A volume Bragg grating (VBG) acted as the input mirror which enables wavelength selection of the Tm:Y2O3 laser. The gold-nanorods-based saturable output coupler combined the function of passive Q-switching and output coupling. In the CW mode, the VBG-locked Tm:Y2O3 ceramic laser generated 1.1 W at 2101.5 nm with a linewidth (FWHM) of 0.4 nm. In the passively Q-switched operation, pulses with a maximum average output power of 455 mW, a minimum pulse width of 609 ns, and a pulse repetition rate of 79 kHz were achieved. Our work provides a more compact and efficient design for obtaining a nanosecond 2.1 μm laser.

15 GHz picosecond pulse generation from a monolithic waveguide laser with a graphene-film saturable output coupler

We fabricate a saturable absorber mirror by coating a graphene- film on an output coupler mirror. This is then used to obtain Q-switched mode-locking from a diode-pumped linear cavity channel waveguide laser inscribed in Ytterbium-doped Bismuthate Glass. The laser produces 1.06 ps pulses at ~1039 nm, with a 1.5 GHz repetition rate, 48% slope efficiency and 202 mW average output power. This performance is due to the combination of the graphene saturable absorber and the high quality optical waveguides in the laser glass.

Mode Evolution and Lasing Characteristics of a Passively Mode-locked Nd:YAG Laser with a Saturable Output Coupler (SOC)

Mode Evolution and Lasing Characteristics of a Passively Mode-locked Nd:YAG Laser with a Saturable Output Coupler (SOC)

Robust diode-end-pumped Nd:GdVO4 laser passively mode-locked with saturable output coupler

Passively mode-locked diode-pumped solid-state (DPSS) Nd:GdVO4 laser by using a saturable output coupler (SOC) in stable two-mirror linear cavity design is demonstrated. The laser was pumped by low-power single laser diode without any active cooling and external optics. Robust CW mode-locked operation was obtained with a repetition of 150–250 MHz, the pulsewidth was 12 ps, the lowest threshold for CW mode-locked was 185 mW. The optimal condition is found when the laser provides the set of characteristics: low CW mode-locking threshold (∼260 mW), compact size (total cavity length 60 cm), good efficiency (∼20%), and very stable output. At the output power of 270 mW an average power fluctuations within ±2% for long-term operation was obtained.