We offer fs-Kits for efficient third harmonic generation (THG) of femtosecond Yb:fiber lasers or Yb:KGW lasers @ 1025-1045nm. Each THG kit consists of the following parts,

(1) A nonlinear crystal for Type I second harmonic generation (SHG),
(2) A time delay compensator to be inserted between the SHG and the THG crystals to optimize the temporal overlap of the pulses in the THG crystal and subsequently the THG conversion efficiency,
(3) A dual waveplate to turn the orthogonal polarizations from the SHG crystal into parallel polarizations (If Type I THG is selected). The waveplate is ultrathin (~ 60μm) single-plate, true zeroth order to maximize the bandwidth and to minimize the dispersion,
(4) A nonlinear crystal for Type I or Type II sum frequency mixing to generate the THG.

The aperture of the crystals can be 5 to 15mm to be compatible with a specific laser.  Extensions with harmonic separators, crystal for 4th harmonic generation, waveplate/polarizer power adjuster, or opto-mechanics are available upon request. 

As the pulse width, pulse energy and the average power of an ultrafast fiber laser can vary in very large ranges,  the nonlinear crystals can be LBO or BBO crystals depending on the actual laser parameters to maximize the total THG conversion efficiency without the pulse broadening.  For a high power application, the crystals need to be mounted in an oven or water-cooled holder to stabilize the crystal temperature.

Please send us an inquiry with your laser parameters (the central wavelength, pulse energy, repetition rate, and the beam size).  We will make a  recommendation for the THG kit.