Diode-pumped passively Q-switched and mode-locked Nd:Lu<Subscript>0.15</Subscript>Y<Subscript>0.85</Subscript>VO<Subscript>4</Subscript> laser with a GaAs saturable absorber

By using a-cut Nd:Lu_0.15Y_0.85VO₄ mixed crystal as laser gain medium, a diode-pumped passively Q-switched and mode-locked (QML) laser with a GaAs saturable absorber in a Z-type folded cavity is demonstrated for the first time. The Q-switched mode-locked laser pulses with about 90% modulation depth are obtained as long as the pump power reached the oscillation threshold. The repetition rate of the passively Q-switched pulse envelope ranges from 50 to 186 kHz as the pump power increases from 0.915 to 6.520 W. Under an incident pump power of 6.52 W, the QML pulses with the largest average output power of 694 mW, the shortest pulse width of 200 ns and the highest pulse energy of 3.73 μJ are obtained. The mode-locked pulse width inside the Q-switched envelope is estimated to be about 275 ps. The experimental results show that Nd:Lu_0.15Y_0.85VO₄ is a promising mixed crystal for QML laser.     

Diode-pumped passively mode-locked Nd:CaNb<Subscript>2</Subscript>O<Subscript>6</Subscript> laser

We have experimentally demonstrated a diode-pumped passively mode-locked Nd:CaNb₂O₆ laser for the first time to our best knowledge. With a semiconductor saturable absorber mirror (SESAM) as a passive mode locker, the laser generated stable mode-locked pulses with pulse duration of 17.3 ps and repetition rate of 88.4 MHz. With a singe-emitter laser diode pumping, the maximum average output power of the mode-locked laser was 0.843 W, with a slope efficiency of 23%. The experimental results show the Nd:CaNb₂O₆ crystal is a promising laser gain medium for picosecond pulse generation.     

Q-switched and continuous-wave mode-locking of a diode-pumped Nd:Gd0.64Y0.36VO4−Cr4+:YAG laser

We report on a diode-pumped passively mode-locked Nd:Gd_0.64Y_0.36VO₄ laser with a Cr⁴⁺:YAG saturable absorber. Q-switched mode locking (QML) with 90% modulation depth was obtained. The peak power of the mode-locked pulse near the maximum of the Q-switched envelope was estimated to be about 1.7 MW at the pump power of 12 W. Besides QML, continuous-wave mode locking was also experimentally realized, for the first time to our knowledge, in the laser under a strong intracavity pulse energy fluence. The mode-locked pulse width is about 2.96 ps at a repetition rate of 161.3 MHz.     

High power passively mode-locked Nd:YVO<Subscript>4</Subscript> laser using graphene oxide as a saturable absorber

We report on a passively mode-locked Nd:YVO₄ laser using a novel graphene oxide saturable absorber fabricated by vertical evaporation method. An 880 nm LD pump source was used to reduce the thermal load of the laser crystal. At the pump power of 7.4 W, 1.2 W average output power of continuous wave mode-locked laser with optical conversion efficiency of 16.2% was achieved. To the best of our knowledge, this is the highest output power of passively mode-locked solid-state laser using graphene oxide saturable absorber. The repetition rate of passively mode-locked pulse was 88 MHz with the pulse energy of 13.6 nJ.     

Experimental study on a diode-pumped passively mode-locking Nd:GdVO<Subscript>4</Subscript>/SESAM laser

We demonstrate a low-threshold and efficient diode-pumped passively continuous wave (CW) mode-locked Nd:GdVO₄ laser with a reflective semiconductor saturable absorber mirror (SESAM). The threshold for the continuous wave was 0.36 W, and it is the lowest threshold for a continuous wave in a passively mode-locked Nd:GdVO₄ laser to our knowledge. The maximum average output power of 1.82 W was obtained at a pump power of 6.65 W with a slope efficiency of about 29%. The CW mode-locked pulse duration was measured to be about 10.5 ps with a 116-MHz repetition rate.     

Diode-pumped passively mode-locked Yb:LSO/SESAM laser

Diode-end-pumped passively mode-locked Yb³⁺:Lu₂SiO₅ (Yb:LSO) lasers both in the picosecond and the femtosecond regimes were demonstrated in this paper. The mode-locked lasers were initiated by using of semiconductor saturable absorber mirrors (SESAM). In the absence of intra-prisms for pulse compression, the laser emitted 1.6 W of output power with pulses width of about 4.3 ps. A pair of SF10 prisms was inserted into the laser cavity, pulses as short as 699 fs was generated around a center wavelength of 1043.6 nm with an average output power of 800 mW and a peak power of 11.0 kW.     

High efficiency passive mode-locked Nd:YVO<Subscript>4</Subscript> laser based on SESAM under direct pumping at 880 nm

We report on an 880 nm LD pumped passive mode-locked TEM₀₀ Nd:YVO₄ laser based on a semiconductor saturable absorber mirror (SESAM), with a high optical-to-optical conversion efficiency of 67.3%, and a slope efficiency of 71%. When the absorbed pump power was 11 W, 7.4 W average output power of 1064 nm continuous-wave mode-locked laser was achieved. To our knowledge, this is the highest optical-to-optical conversion efficiency among all the published reports of 880 nm LD pumped SESAM passive mode-locked lasers. The repetition rate of mode-locked pulse was 80 MHz with 26 ps pulse width. The maximum pulse energy and peak power were 92.5 nJ and 3.6 kW, respectively.     

Diode-end-pumped passively mode-locked Nd:LuVO4 laser with a semiconductor saturable-absorber mirror

A diode pumped passively mode-locked Nd:LuVO₄ laser with a semiconductor saturable-absorber mirror (SESAM) is demonstrated. The mode-locked pulses have a pulse duration of about 8.8 ps and a repetition rate of 157 MHz. Under an absorbed pump power of 12 W a maximum output power of 3.71 W is obtained, which gives an optical conversion efficiency of 31%. Our results show that Nd:LuVO₄ is a promising gain medium for the high power mode-locked solid-state lasers.     

Passive mode-locked Nd:YVO<Subscript>4</Subscript> laser using a multi-walled carbon nanotube saturable absorber

We report a passive mode-locked Nd:YVO₄ laser pumped by 880 nm LD using a transmission-type multi-walled carbon nanotube saturable absorber. At the pump power of 6.1 W, the average output power of 0.8 W of continuous wave mode-locked laser with optical conversion efficiency of 13.1% was generated. The repetition rate and pulse energy of the mode-locked pulse were 88 MHz and 9.1 nJ, respectively.     

Compact and efficient Kerr-lens mode-locked diode-pumped actively Q-switched YVO4-Nd:YVO4 laser

By using a simple linear configuration, a stable and efficient YVO₄-Nd:YVO₄ laser, actively Q-switched by an acousto-optic modulator and passively mode-locked by KLM is realized, from which the great average output power, the high efficiency are obtained and the mode-locked pulse inside the Q-switched pulse has a repetition rate of 470 MHz. The nearly 100% modulation depth of the Q-switched mode-locked pulses can be obtained at any pump power over the threshold. Considering the Kerr-lens effect of laser medium and Q-switching by an acousto-optic modulator, we have analyzed the self-mode-locked YVO₄-Nd:YVO₄ laser by using the nonlinear ABCD propagation matrix and the hyperbolic fluctuation mechanism. The numerical solutions are in good agreement with the experimental results.     

Self-Q-switched and mode-locked 946 nm Cr,Nd:YAG laser

A simultaneous self-Q-switched and mode-locked diode-pumped 946 nm laser by using a Cr,Nd:YAG crystal as gain medium as well as saturable absorber is demonstrated for the first time as we know. The maximum average output power of 751 mW with a slope efficiency of 18.38% is obtained at an intra-cavity average peak power intensity of 4.83 × 10⁶ W/cm². Under this circumstance, the repetition rate of Q-switched envelopes is 9.63 kHz and the pulse width is about 460 ns. Almost 100% mode-locked modulation depth is obtained at all time in the experiment process whether the incident pump power is low or high. The repetition rate of mode-locked pulses within a Q-switched envelope is 135.13 MHz and the mode-locked pulse width is within 600 ps. The laser produces high-quality pulses in TEM₀₀-mode in the simultaneous self-Q-switched and mode-locked experiment.     

Ultrafast laser performance of Yb3 +: Sc2SiO5 crystal with a single-walled carbon nanotube absorber

Single-walled carbon nanotube (SWCNT) absorber fabricated by vertical evaporation is used in passively mode-locked Yb^3 +:Sc₂SiO₅ (Yb:SSO) ultrafast laser for the first time. The performance of Yb:SSO ultrafast laser with pulse width as short as 880 fs is studied and the average output power is 712 mW. To our knowledge, this is the highest output power of femtosecond lasers with SWCNT-SAs reported. In addition, we firstly demonstrate a passively mode-locked picosecond Yb:SSO laser without inserting any dispersion compensation device. The pulses width is as short as 5.4 ps and the output power is 940 mW.     

Passively mode-locked Yb:LYSO laser with a reflection type single-walled carbon absorber

Passively diode-pumped Yb:LuYSiO₅ (Yb:LYSO) laser mode locked by reflection-type single walled carbon nanotubes saturable absorber (RSWCNT-SA) is reported for the first time. Under the absorbed pump power of 13.23 W, continuous wave (CW) mode-locked pulses were generated with the maximum average output power of 157 mW. We obtained pulses as short as 4.0 ps around a center wavelength of 1038.3 nm. The peak power and the single pulse energy of the mode-locked laser were 0.38 kW and 1.52 nJ, respectively.     

Diode-pumped passively Q-switched mode-locked Nd:LuVO4 laser with a semiconductor saturable absorber mirror

We present a compact passively Q-switched mode-locked Nd:LuVO₄ laser run in a Z-type folded cavity with semiconductor saturable absorber mirror (SESAM). The repetition rates of the passively Q-switched pulse envelope ranges from 22.99 to 141.18 kHz as the pump power increased from 2.372 to 8.960 W. The repetition rates of mode-locked laser pulses in the Q-switched pulse envelope has 111 MHz determined by the cavity length and the mode-locked pulse duration is evaluated to be 257 ps. An average output power of 823.5 mW is achieved at the pump power of 8.96 W, corresponding to an optical conversion efficiency of 9.2%.     

Diode array pumped, non-linear mirror Q-switched and mode-locked Nd : YVO4 laser — a good tool for powder SHG measurement

A non-linear mirror consisting of a lithium triborate crystal and a dichroic output coupler are used to mode-lock (passively) an Nd : YVO₄ laser, pumped by a diode laser array. The laser can operate both in cw mode-locked and simultaneously Q-switched and mode-locked (QML) regime. The peak power of the laser while operating in QML regime is much higher but pulses suffers from poor amplitude stability. The incorporation of an acousto-optic modulator as an active Q-switch enhances the stability of the QML pulse envelope. The second-order non-linearity of powdered crystalline urea is conclusively measured with respect to KDP while the laser is operating in passively Q-switched and passively mode-locked regime as well as in actively Q-switched and passively mode-locked regime.     

High-power diode-directly-pumped tenth-order harmonic mode-locked TEM00 Nd:YVO4 laser with 1 GHz repetition rate

A high-efficiency high-power diode-directly-pumped tenth-order harmonic mode-locked TEM₀₀ Nd:YVO₄ laser with 1 GHz repetition rate was first demonstrated. The maximum output power was 10.4 W with optical-optical efficiency of 41.8% and slope efficiency of 78.1%, respectively, the pulse width was about 30 ps at the output power of 9.6 W. Based on the large third-order nonlinearity of Nd:YVO₄, the tenth-order harmonic mode-locked pulses were induced by the intensity-dependent Kerr effect and the cooperative action of counter-propagating pulses colliding in the laser crystal for a colliding-pulse-modelocking-like cavity. The pulses were further modulated by a semiconductor saturable absorber mirror.     

Diode-pumped passively Q-switched mode-locking Nd:Y0.5Gd0.5VO4 laser at 1.34 μm with Co2+:LaMgAl11O19 saturable absorber

We reporte a passively Q-switched and mode-locked Nd:Y_0.5Gd_0.5VO₄ laser at 1.34 μm with Co²⁺:LaMgAl₁₁O₁₉(Co:LMA) crystal as the saturable absorber. With the incident pump power of 6.56 W, a maximum output power of 242 mW was obtained. Q-switched mode-locking pulses with modulation depth nearly 100% were obtained. The width of the mode-locked pulse was estimated to be less than 600 ps.     

Nd:YVO4自受激拉曼激光器调Q锁模特性

利用Nd:YVO4激光晶体的自受激拉曼效应,结合Cr:YAG被动锁模技术和倍频技术,实现了结构紧凑的1176 nm和588 nm黄光锁模激光输出。激光器为LD端面泵浦,三镜折叠腔结构,并且采用了透过率为10%的输出镜。Nd:YVO4晶体长度为10 mm,Nd3+离子掺杂质量分数为0.2%,Cr:YAG晶体的初始透过率为67%。10 W激光泵浦时,1176 nm激光平均输出功率为123 mW,调Q包络宽度为6 ns,调Q包络内的锁模脉冲重复频率高达1 GHz。588.2 nm 黄光的平均输出功率为8 mW。     

Passive mode locking of a diode-pumped Nd:Gd 0.64 Y 0.36 VO 4 laser with a GaAs saturable absorber mirror

We report a diode-pumped Nd:Gd_0.64Y_0.36VO₄ laser passively mode locked by using a GaAs saturable absorber mirror. Both the Q-switched and continuous-wave (CW) mode locking were experimentally realized. The CW mode-locked pulses have a pulse width of about 8.8 ps at a repetition rate of 161.3 MHz. Limited by the available pump power, a maximum output power of 2.47 W was obtained for the CW mode-locked pulses with a slope efficiency of about 26.6%.     

Passive mode-locking in diode-pumped c-cut Nd:LuVO<Subscript>4</Subscript> laser with a semiconductor saturable-absorber mirror

We demonstrated a diode-pumped passively mode-locked c-cut Nd:LuVO₄ picosecond laser with a semiconductor saturable-absorber mirror (SESAM) at a wavelength of 1067.8 nm. Due to the wide bandwidth of 0.48 nm, stable mode-locking has been generated with a duration as short as 3.7 ps, which is shorter than for the a-cut Nd:LuVO₄ laser. A maximum output power of 1.67 W was achieved to give a highest peak power of 3.47 KW at 18 W absorbed pump power.