Passively Q-Switched Nd,Cr:YAG Laser Simultaneous Dual-Wavelength Operation at 946 nm and 1.3μm

A diode-end-pumped Q-switched high-efficiency Nd, Cr：YAG laser with simultaneous dual-wavelength emission at 946nm and 1.3μm is demonstrated. The maximum output power of 1.93 W with simultaneous dual-wavelength operation is achieved at an absorbed pump power of 13.32 W and an absorbed slope efficiency of 15.15%. The maximum optical-optical efficiency is 14.49% with pulse widths of 16.38ns at 946nm and 26.65ns at 1.3μm. A maximum total repetition rate of 43.25 kHz is obtained.

Dual-wavelength dissipative soliton operation of an erbium-doped fibre laser using a nonlinear polarization rotation technique

We report on the generation of dual-wavelength dissipative solitons in a passively mode-locked fibre laser with a net normal dispersion using the nonlinear polarization rotation （NPR） technique. Taking the intrinsic advantage of the intracavity birefringence-induced spectral filtering effect in the NPR-based ring laser cavity, the dual-wavelength dissipative solitons are obtained. In addition, the wavelength separation and the lasing location of the dual-wavelength solitons can be flexibly tuned by changing the orientation of the polarization controller.

Reflective graphene oxide absorber for passively mode-locked laser operating at nearly 1μm

A low cost and simply fabricated reflective graphene oxide is successfully made. By using this absorber, as well as an end reflector, we obtain a passively mode-locked Yb：LuYSiO5 laser operating at nearly 1 p,m. When the pump power is increased up to 5.73 W, stable mode locking is achieved. The central wavelength of the laser spectrum is 1043.2 nm with a pulse duration of 5.0 ps. When the pump power reaches 8.16 W, dual-wavelength mode locking laser pulses at 1036.3 nm and 1043.5 nm are simultaneously detected.

Observation of stable bound soliton with dual-wavelength in a passively mode-locked Er-doped fiber laser

A phase-locked bound state soliton with dual-wavelength is observed experimentally in a passively mode-locked Erdoped fiber（EDF） laser with a fiber loop mirror（FLM）. The pulse duration of the soliton is 15 ps and the peak-to-peak separation is 125 ps. The repetition rate of the pulse sequence is 3.47 MHz. The output power is 11.8 mW at the pump power of 128 mW, corresponding to the pulse energy of 1.52 nJ. The FLM with a polarization controller can produce a comb spectrum, which acts as a filter. By adjusting the polarization controller or varying the pump power, the central wavelength of the comb spectrum can be tuned. When it combines with the reflective spectrum of the fiber Bragg grating, the total spectrum of the cavity can be cleaved into two parts, then the bound state soliton with dual-wavelength at 1549.7 nm and 1550.4 nm is obtained.

Generation of Q-Switched Mode-Locked Erbium-Doped Fiber Laser Operating in Dark Regime

We demonstrate a stable Q-switched mode-locked erbium-doped fiber laser （EDFL） operating in dark regime based on the nonlinear polarization rotation technique. The EDFL produces a pulse train where the Q-switching envelope is formed by multiple dark pulses. The repetition rate of the Q-switched envelope can be increased from 0.96kHz to 3.26kHz, whereas the pulse width reduces from 211 #s to 86#s. The highest pulse of 479nJ is obtained at the pump power of 55 mW. It is also observed that the dark pulses inside the Q-switching envelope consist of two parts： square and trailing dark pulses. The shortest pulse width of the dark square pulse is obtained at 40.5μs when the pump power is fixed at 145mW. The repetition rate of trailing dark pulses can be increased from 27.62kHz to 50kHz as the pump power increases from 55mW to 145mW.

Application of the Sampling and Replication Operators to Describe Mode-Locked Radiation

Sampling and replication operators are used for a description of the mode-locking radiation. Such description allows taking into account the influence of the shape of the gain curve of the active medium of the mode-locking laser on the form of the pulses generated by it.

Passive Q-switching and Q-switched mode-locking operations of 2 μm Tm:CLNGG laser with MoS2 saturable absorber mirror

With MoS2 as saturable absorber, passive Q-switching and Q-switched mode-locking operations of a Tm-doped calcium lithium niobium gallium garnet（Tm:CLNGG） laser were experimentally demonstrated. The Q-switched laser emitted a maximum average output power of 62 mW and highest pulse energy of 0.72 μJ. Q-switched mode locking was also obtained in the experiment. The research results will open up applications of MoS2 at the mid-infrared wavelength.

Intracavity configuration for tuning and obtaining simultaneous dual-wavelength operation from CW Nd:YAG laser

In this letter, a thin slab of glass is used as Fabry-Perot etalon inside a cavity of a continuous wave （CW） Nd：YAG laser to change the behavior of its output longitudinal modes. The slab etalon is used as tuning element when it turns around the laser cavity axis. Two simultaneous longitudinal modes with a relatively wide tuning range from 5.83 MHz to 0,02 THz are obtained when the Nd：YAG laser is operated at moderate output power of about 120 roW. The mode structure of this configuration is modeled and simulated. Computer-generated diagrams are also presented schematically and compared with the experimental results.

Efficient dual-wavelength operation of Nd:LYSO laser by diode pumping aimed toward the absorption peak

By aiming the pump wavelength of the laser （Ndo.oo5Luo.4975Yo.4975）2SiO5 （Nd：LYSO） crystal 1 079 nm is obtained. The maximum output power corresponding to an optical conversion efficiency of diode to the absorption peak at 811 an efficient dual-wavelength operation at 1 is 702 mW when the incident pump power is 27.7% and a slope efficiency of 37.0% of the 075 and 2.53W,

Mode-locked fiber laser in the C-band region for dual-wavelength ultrashort pulses emission using a carbon nanotube saturable absorber

A saturable absorber is commonly employed to generate an ultrashort laser with a mode-locking scheme. In an erbium-doped fiber laser system, the laser regimes of either 1530 or 1550 nm wavelength are procured based on the absorption profile of the erbium-doped fiber. The absorption of the erbium-doped fiber is designed to emit at both wavelengths by controlling the net gain of the laser cavity. Subsequently, simultaneous erbium-doped fiber laser emission is attained at 1533.5 and 1555.1 nm with the pulse duration of 910 and 850 fs, respectively.Therefore, this work maximizes the output portfolios of a mode-locking fiber laser for dual-wavelength ultrashort pulses emission.

Switchable single-and dual-wavelength femtosecond mode-locked Er-doped fiber laser based on carboxyl-functionalized graphene oxide saturable absorber

In this Letter, we demonstrated the switchable single-and dual-wavelength femtosecond soliton generation in single-mode Er-doped fiber lasers with the usage of carboxyl-functionalized graphene oxide(GO-COOH) saturable absorbers(SAs) for the first time, to the best of our knowledge. The fiber laser generated a stable single-wavelength conventional soliton at 1560.1 nm with a pulse duration of 548.1 fs. The dual-wavelength solitons centered at 1531.9 nm and 1555.2 nm with a spacing of approximately 23 nm can be obtained by adjusting the pump power of the cavity. Our experimental results indicated the GO-COOH has great potential to be used in ultrafast fiber lasers as broadband SAs.

Dual-wavelength synchronously mode-locked Tm-doped bulk laser with terahertz frequency beating

A dual-wavelength synchronously mode-locked homogeneously broadened bulk laser operating at 1985.6 and1989 nm is presented for the first time, to the best of our knowledge, which delivers a maximum output power of 166 m W and a repetition rate of 85 MHz. The pulse duration was measured to be 16.8 ps by assuming a sech2 pulse shape. The recorded autocorrelation trace showed frequency beating signals with an interval of 3.8 ps and a full width at half-maximum duration of 2 ps, corresponding to an ultrahigh beating frequency of about0.26 THz, which agrees well with the frequency difference of the emitted two spectral peaks. The results indicated that such a kind of dual-wavelength mode-locked Tm:YAlO3 laser could be potentially used for generating terahertz radiations.

Yb:CaF_(2)-YF_(3)transparent ceramics ultrafast laser at dual gain lines

Yb^(3+):CaF_(2)–YF_(3)transparent ceramics with excellent optical quality was successfully fabricated by hot-pressed method.Pulsed laser properties of this ceramics were investigated for the first time.Laser diode(LD)was applied as the pump source to generate a dual-wavelength mode-locked(ML)laser.The maximum average output power was 310 mW,which represents the highest output power of ultrafast calcium fluoride ceramic laser.The spectrum separated at 1048.9 nm and 1049.7 nm with a total pulse duration of 8.9 ps.The interval period between the beating signals was about 4.3 ps,corresponding to a 0.23 THz beat pulse repetition rate.These results demonstrate its potential in producing dual-wavelength ultrashort pulses.These Yb^(3+):CaF_(2)–YF_(3)ceramics with low-cost and short-preparation period are ideal candidate materials for ultrafast lasers.