基于氧化石墨烯的瓦级调Q锁模Tm:LuAG激光器

在Tm:LuAG全固态激光器中实现了以氧化石墨烯可饱和吸收体为锁模启动元件的瓦级被动调Q锁模运转.本实验装置以可调谐掺钛蓝宝石激光器作为泵浦源,测得Tm:LuAG固态激光器出光阈值最低为325mW,当吸收抽运功率达到3420 mW时,进入稳定的调Q锁模运行状态.当抽运功率达到8.1 W时,对应的最大输出功率为1740 mW,中心波长为2023 nm,重复频率为104.2 MHz,最大单脉冲能量为16.7 nJ,调制深度接近100%.     

基于单壁碳纳米管调Q锁模低阈值Tm,Ho:LiLuF_4激光器

采用垂直生长法制作的单壁碳纳米管作为可饱和吸收体,结合特殊的低阈值谐振腔设计,首次在Tm,Ho:LiLuF_4全固态激光器中实现了低阈值自启动被动调Q锁模运转.以波长可调的掺钛蓝宝石固体激光器作为抽运源,选用1.5%,3%和5%的输出耦合镜,获得了出光阈值低至52,59和62mW的连续光输出.采用3%输出耦合镜,获得了阈值低至250mW的稳定调Q锁模脉冲输出,调Q包络的脉宽为2μs,调Q包络下锁模脉冲重复频率178.6MHz,最大输出功率154mW,最大的单脉冲能量为0.86nJ,调制深度接近100%.     

连续锁模Nd：YVO4激光器实现1 GHz高频输出

LD抽运全固体Nd:YVO4激光器在连续锁模状态运转下获得了高达1 GHz的重复频率.实验中采用半导体可饱和吸收镜作为锁模元件.利用透过率只有0.8%的输出镜以及可获得较小抽运光斑的2 W LD作为抽运源来优化激光器设计,有效地抑制了调Q锁模状态的运转.低的激光器振荡阈值（35 mW）和连续锁模阈值(0.8 W)显示了饱和吸收体低的插入损耗和激光器合理的设计.在最大抽运1.6 W时获得了210 mW的平均输出功率.     

Diode-pumped femtosecond Yb:CaNb2O6 laser

We report to our knowledge a diode-pumped passively mode-locked Yb:CaNb(2)O(6) (Yb:CN) laser for the first time. Both CW and passive mode-locking operation of the laser are experimentally investigated. A maximum CW output power of 1.4 W with a slope efficiency of 20% is obtained on a 7 mm long 1.5 at.% Yb:CN crystal, while stable passive mode-locking with a commercial semiconductor saturable absorption mirror (SESAM) was achieved on a 3 mm long 3 at.% Yb:CN crystal. The mode-locked pulses have pulse width of 251 fs and an average output power of 44 mW at 1038 nm.     

连续锁模Nd∶YVO4激光器实现1 GHz高频输出

LD抽运全固体Nd∶YVO4激光器在连续锁模状态运转下获得了高达1 GHz的重复频率.实验中采用半导体可饱和吸收镜作为锁模元件.利用透过率只有0.8%的输出镜以及可获得较小抽运光斑的2 WLD作为抽运源来优化激光器设计,有效地抑制了调Q锁模状态的运转.低的激光器振荡阈值(35 mW)和连续锁模阈值(0.8 W)显示了饱和吸收体低的插入损耗和激光器合理的设计.在最大抽运1.6 W 时获得了210 mW的平均输出功率.     

基于石墨烯的1 064 nm连续锁模超短脉冲激光器

介绍了利用沉积在增透镜上的石墨烯薄膜作为可饱和吸收体、808 nm激光二极管端面泵浦Nd∶YVO4晶体的1 064 nm连续锁模激光输出特性。采用W型折叠谐振腔结构,在808 nm泵浦功率为8.0 W时,有稳定的连续锁模脉冲输出,平均输出功率达到185 mW;当抽运功率增加到16.0 W时,获得了中心波长1 063.4 nm、脉冲宽度为518 fs、重复频率为66.7 MHz、最大平均输出功率为323 mW的百飞秒量级超短脉冲激光输出。实验结果表明:石墨烯具有优良的可饱和吸收性,在1 064 nm波段能够实现高功率、百飞秒量级连续锁模脉冲激光输出。     

Diode-pumped mode-locked femtosecond Tm:CLNGG disordered crystal laser

A diode-end-pumped passively mode-locked femtosecond Tm-doped calcium lithium niobium gallium garnet (Tm:CLNGG) disordered crystal laser was demonstrated for the first time to our knowledge. With a 790 nm laser diode pumping, stable CW mode-locking operation was obtained by using a semiconductor saturable absorber mirror. The disordered crystal laser generated mode-locked pulses as short as 479 fs, with an average output power of 288 mW, and repetition rate of 99 MHz in 2 μm spectral region.     

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 actively mode-locked Tm:YAlO3 laser

CW acousto-optical mode-locked diode pumped Tm:YAlO₃ laser at 1.936 μm was experimentally studied. Lasing with output power ～100 mW, pulse repetition rate 103.4 MHz and laser pulse durations in the range of 30–200 ps was realized. The problem of laser intensity stabilization is discussed.     

532-nm picosecond pulse generated in a passively mode-locked Nd:YVO_4 laser

A diode-pumped continuous-wave （CW） mode-locked Nd：YVO4/KTP green laser with semiconductor saturable absorber mirror （SESAM） is demonstrated. The maximum output power of CW mode-locked green laser is obtained to be 552 mW at the incident pump power of 7.25 W, corresponding to an opticai-optical conversion efficiency of about 7.6%. The 532-nm CW mode-locked pulse duration is estimated to be about 8.4 ps with the repetition rate of 87 MHz.     

Highly efficient, low-cost femtosecond Cr3+ :LiCAF laser pumped by single-mode diodes

We describe efficient continuous-wave (cw) and cw mode-locked operations of a Cr3+ :LiCAF laser, pumped by inexpensive single spatial mode laser diodes. Up to 280 mW of cw output power was obtained with 570 mW of absorbed pump power, with a corresponding slope efficiency of 54%. Continuous tuning between 765 and 865 nm was demonstrated using a fused silica prism. A semiconductor saturable absorber mirror was used to initiate and sustain stable, self-starting, mode-locked operation. In cw mode locking, the laser produced 72 fs (FWHM) duration pulses, and 1.4 nJ pulse energy, at an average output power of 178 mW. Electrical to optical conversion efficiencies of 7.8% in mode-locked operation and 12.2% in cw operation were demonstrated.     

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.     

CW and Q-switched diode-pumped laser operation of Yb3+:NaLa(MoO4)2

Continuous wave (CW) and Q-switched diode-pumped laser operation of Yb³⁺:NaLa(MoO₄)₂ single crystal was to our knowledge, demonstrated for the first time. A CW output power of 220 mW and slope efficiency of 46% were obtained. Q-switched laser operation was achieved with a pulse duration of 60 ns average output power of 70 mW and slope efficiency of 22%. PACS 42.55.Xi; 42.60.Pk; 42.60.Gd.     

被动锁模Yb3+光纤环形腔激光器的研究

 采用974 nm半导体激光器作为泵浦源，超高掺杂Yb³⁺光纤作为增益介质，利用光纤的非线性偏振旋转效应，得到稳定的ps量级锁模光脉冲。泵浦功率220 mW时，激光器锁模阈值功率150 mW，输出功率26 mW，锁模光脉冲中心波长1 046 nm，3 dB带宽6.01 nm，20 dB带宽16 nm，脉宽22 ps，重复频率20 MHz。与同类光纤激光器相比，该激光器输出功率高，具有更好的稳定性。     

LD end-pumped passively mode-locked Nd:YVO<Subscript>4</Subscript> laser with single-walled carbon nanotubes

We demonstrate a LD end-pumped passively mode-locked Nd:YVO₄ laser using a single-walled carbon nanotubes saturable absorber (SWCNT-SA). The SWCNT wafer was fabricated by electric arc discharge method on quartz substrate with absorption wavelength of 1064 nm. At the absorbed pump of 15.8 W, an output power of 750 mW CW (continuous wave) mode-locked laser pulse was achieved with the repetition of 79.7 MHz, corresponding to optical-optical efficiency of 4.75%.     

2089 nm调Q锁模Tm,Ho∶CaYAlO4激光器

首次采用氧化石墨烯可饱和吸收体作为锁模启动元件在Tm,Ho∶CaYAlO4激光器中实现了稳定的被动调Q锁模运转。在3%输出耦合镜下,Tm,Ho∶CaYAlO4固体激光器获得了最低为293 mW的连续光出光阈值。在腔内引入氧化石墨烯可饱和吸收体后,当吸收抽运功率增大到1859 mW时,Tm,Ho∶CaYAlO4激光器进入稳定的调Q锁模运转状态。当抽运功率达到3 W时,获得中心波长为2089 nm、斜效率为10.1%、对应最大输出功率为213 mW的被动调Q锁模脉冲,重复频率为100 MHz,调Q包络中锁模脉冲的调制深度接近100%。     

Efficient yellow beam generation by intracavity sum frequency mixing in DPSS Nd:YVO4 laser

We present our studies on dual wavelength operation using a single Nd:YVO₄ crystal and its intracavity sum frequency generation by considering the influence of the thermal lensing effect on the performance of the laser. A KTP crystal cut for type-II phase matching was used for intracavity sum frequency generation in the cavity at an appropriate location for efficient and stable yellow output power. More than 550 mW of stable CW yellow-orange beam at 593.5 nm with beam quality parameter (M ²) ～4. 3 was obtained. The total pump to yellow beam conversion efficiency was estimated to be 3.83%.     

Contrastive study of two SESAMs for passive mode-locking in Nd:YVO4 laser with low pump power

Two semiconductor saturable absorber mirrors (SESAMs), of which one is coated with 50% reflection film on the top and the other is not, were contrastively studied in passively mode-locked solid-state lasers which were pumped by low output power laser diode (LD). Experiments have shown that reducing the modulation depth of SESAM by coating partial reflection film, whose reflectivity is higher than that between SESAM and air interface, is an effective method to get continuous wave (CW) mode-locking instead of Q-switched power LD, in which no water-cooling system was used, could obtain CW mode-locking by the 50% reflector coated SESAM with average output power of ～ 20 mW.     

被动锁模Yb3+光纤环形腔激光器的研究

采用974 nm半导体激光器作为泵浦源,超高掺杂Yb3+光纤作为增益介质,利用光纤的非线性偏振旋转效应,得到稳定的ps量级锁模光脉冲。泵浦功率220 mW时,激光器锁模阈值功率150 mW,输出功率26 mW,锁模光脉冲中心波长1 046 nm,3 dB带宽6.01 nm,20 dB带宽16 nm,脉宽22 ps,重复频率20 MHz。与同类光纤激光器相比,该激光器输出功率高,具有更好的稳定性。     

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%.