Wenlong Tian

Efficient femtosecond mode-locked Nd,Y:SrF2 laser

An efficient femtosecond mode-locked laser using Nd and Y-codoped SrF2 crystal as the gain medium is presented in this letter. A 332 fs pulse centered at 1057 nm with a repetition rate of 89.8 MHz, a spectral width of 4.3 nm, and a mode-locked output power of up to 395 mW has been obtained under 1 W pump power, corresponding to an optical-to-optical efficiency of 39.5% and a slope efficiency of 69%. To the best of our knowledge, this is the highest optical efficiency in femtosecond Nd-doped crystal lasers.

Diode-pumped passively mode-locked Yb:GYSO laser generating 324 fs pulses at 1091 nm

We report the first demonstration of femtosecond operation in a diode-pumped Yb-doped GdYSiO5 (Yb:GYSO) laser. With a semiconductor saturable absorber mirror for passive mode locking and a pair of SF6 prisms for intracavity dispersion compensation, we realized stable passive mode locking with the new Yb-doped laser material. Femtosecond pulses as short as 324 fs were obtained at the central wavelength of 1091 nm. The maximum average power is 450 mW for an absorbed pump power of 2.8 W, with a slope efficiency of 18.5% and a pulse repetition frequency of 80.1 MHz.

Generation of sub-100 fs pulses from mode-locked Nd,Y:SrF2 laser with enhancing SPM

A mode-locked laser using Nd,Y:SrF2 crystal as the gain medium is presented in this letter. By special design of the cavity for enhancing the self-phase modulation effect, femtosecond mode-locking with 97 fs pulse duration and 13.2 nm spectral width centered at 1061 nm is obtained at a repetition rate of 96 MHz. The average output power is 102 mW under 925 mW pump power, corresponding to the optical-to-optical efficiency of 11%. To the best of our knowledge, these are the first sub-100 fs pulses generated from a mode-locked Nd doped crystal laser.

Generation of 73 fs pulses from a diode pumped Kerr-lens mode-locked Yb:YCa 4 O(BO 3 ) 3 laser

We realized a stable Kerr-lens mode-locked operation in a Yb:YCa₄O(BO₃)₃ laser. Pulses as short as 73 fs were generated at the central wavelength of 1043 nm, with a bandwidth of 19 nm. The femtosecond oscillator operating at a repetition rate of 110 MHz delivers an average output power of 70 mW under 3 W diode pump power. To the best of our knowledge, this is the first demonstration of a pure Kerr-lens mode-locked operation in a diode-pumped Yb:YCa₄O(BO₃)₃ laser.

Diode-pumped Kerr-lens mode-locked Yb:LYSO laser with 61fs pulse duration

A stable diode pumped Kerr-lens mode-locked (KLM) Yb:LuYSiO5 (Yb:LYSO) laser of generating 61 fs pulses at a central wavelength of 1055.4 nm is experimentally demonstrated. This is, to the best of our knowledge, the first demonstration of femtosecond KLM operation in Yb:LYSO laser, and it is believed that 61 fs is the shortest pulse duration ever produced from an Yb-doped orthosilicate laser. The average output power of the mode-locked laser is 40 mW and the repetition rate is 113 MHz.

Diode-pumped self-starting mode-locked femtosecond Yb:YCa4O(BO3)3 laser

A self-starting mode-locked femtosecond laser is accomplished with an oxoborate self-frequency doubling crystal Yb:YCa4O(BO3)3 (Yb:YCOB) as the gain medium and a semiconductor mirror as the saturable absorber. Pumped by a 976-nm fiber-coupled diode laser with 50-μm core diameter, stable mode-locked laser pulses up to 430 mW were obtained at a repetition rate of 83.61 MHz under 5-W pump power. The autocorrelation measurement shows that the pulse duration is as short as 150 fs by assuming the sech2 pulse shape at a central wavelength of 1048 nm. This work has demonstrated a compact and reliable femtosecond laser source for prospective low-cost applications.

Dissipative soliton and synchronously dual-wavelength mode-locking Yb:YSO lasers

We experimentally demonstrate the dissipative soliton mode-locking operation of a Yb:YSO laser by using an all-normal dispersion cavity. Strongly chirped pulses are obtained with pulse duration of 9.3 ps at a repetition rate of 113.4 MHz. The central wavelength is 1082 nm with 3.1 nm FWHM bandwidth. A dual-wavelength synchronously mode-locking operation at central wavelengths of 1059.2 nm and 1082.2 nm is also reported. Stable mode-locked pulses are achieved with pulse duration of 10 ps and total average output power of 164 mW. Periodic ultrashort beat pulses with pulse duration of 169 fs at an ultrahigh repetition rate of 1.4 THz can be distinctly observed from the measured autocorrelation trace. To our knowledge, this is the first demonstration of dual-wavelength synchronously mode-locking operation from a Yb:YSO laser.

High-power, widely tunable, green-pumped femtosecond BiB 3 O 6 optical parametric oscillator.

We report on an efficient high-power, widely tunable femtosecond optical parametric oscillator in BiB3O6, synchronously pumped by a frequency-doubled mode-locked Yb:KGW laser at 515 nm. Using collinear type I (o→e+e) phase matching, a resonant wavelength range of 688-1057 nm at a 151-MHz repetition rate is demonstrated, with a tunable idler range of 1150-1900 nm. The output power at 705 nm is 1.09 W for 3.6 W pump power exceeding 30% conversion efficiency. Near-transform-limited pulses down to 71 fs are achieved by deploying extracavity dispersion compensation in a pair of SF6 prisms.

Diode-Pumped Passively Mode-Locked 1079nm Nd:CaGdAlO

We demonstrate a diode-pumped passively cw mode-locked Nd:CaGdAlO4 laser operating at 1079nm with a semiconductor saturable absorber mirror for the first time to the best of our knowledge. The threshold pump power of the laser is 180mW. A maximum average output power of 93mW is obtained under the pump power of 1.94 W. The pulse duration of the mode-locked pulses is 3.1 ps and the repetition rate is 157 MHz.

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We report a multi-gigahertz (GHz) repetition-rate femtosecond MgO:PPLN optical parametric oscillator (OPO) harmonically pumped by a 75.6 MHz Kerr-lens mode-locked Yb:KGW laser. By fractionally increasing the OPO cavity length, we obtained OPO operation up to the 493rd harmonic of the pump laser repetition rate, corresponding to a repetition rate as high as 37.3 GHz. Using a 1.5% output coupler, we are able to extract signal pulses with up to 260 mW average power at the 102nd harmonic (7.7 GHz) and 90 mW at the 493rd harmonic (37.3 GHz) under 2 W pump power. The measured relative standard deviations of the fundamental and the 102nd harmonic signal power were recorded to be 0.5% and 2.1%, respectively. The signal pulse durations at different harmonics were measured in the range of 160-230 fs.