Masaki Takama

Efficient broadband-spectrum oscillation of ultrashort-pulse Kerr-lens mode-locked Yb:YAG laser with intracavity nonlinear media overcoming the fluorescence spectrum limit

Efficient broadband spectrum oscillation was obtained directly from a laser-diode-pumped Kerr-lens mode-locked Yb:YAG laser with intracavity nonlinear media. The spectrum was expanded to around 1040 nm to 1070 nm. The spectrum is much broader than the fluorescence spectrum at 1050 nm.

Efficient ultrashort-pulse generation of Yb:YAG laser overcoming the fluorescence spectrum limit by using nonlinear medium

One-hundred-ten-fs and 72-fs pulse-widths were obtained directly from a mode-locked Yb:YAG laser with SESAM and without SESAM, respectively. The laser-spectrum-center and the fluorescence-center were almost same. The oscillation-spectra were much broader than the fluorescence.

Twenty-Watt Average Output Power, Picosecond Thin-Rod Yb:YAG Regenerative Chirped Pulse Amplifier with 200 μJ Pulse Energy

A laser-diode-pumped, ps-pulse thin-rod Yb:YAG laser amplifier was developed. The average output power of 20 W was achieved with a output pulse width of 2 ps at a pulse repetition rate of 100 kHz.

High-efficiency cavity-dumped micro-chip Yb:YAG laser

High-efficiency cavity-dumped ytterbium-doped yttrium aluminum garnet (Yb:YAG) laser was developed. Although the high quantum efficiency of ytterbium-doped laser materials is appropriate for high-efficiency laser oscillation, the efficiency is decreased by their quasi-three/four laser natures. High gain operation by high intensity pumping is suitable for high efficiency oscillation on the quasi-three/four lasers without extremely low temperature cooling. In our group, highest efficiency oscillations for continuous wave, nanosecond to picosecond pulse lasers were achieved at room temperature by the high gain operation in which pump intensities were beyond 100 kW/cm2.

Thin-rod Yb:YAG regenerative laser amplifier

High-average-power, high-repetition-rates picosecond-pulsed regenerative ytterbium-doped yttrium aluminum garnet (Yb:YAG) laser amplifiers were developed. The architecture used in the amplifiers, which are named as thin-rod, has a unique cooling scheme like slab lasers and also has a unique pumping scheme like photonic crystal fiber lasers, is suitable for high-average power Ytterbium lasers. This architecture also has high gain characteristics which is appropriate for the regenerative spectral and pulse shaping on high-repetition-rate, ultrashort-pulse amplifications.

Nonlinear Spectral Broadening and Pulse-Narrowing in Ultrashort-Pulse Mode-Locked Laser by Intracavity Highly-Nonlinear Media

Exceeding the fluorescence spectrum limit of the laser gain material, broadband ultrashort pulse generation was obtained directly from mode-locked solid state laser oscillator with intracavity nonlinear medium.

High average output power, picosecond thin-rod Yb:YAG regenerative chirped pulse amplifier with 200 μJ pulse energy

A LD-pumped, thin-rod Yb:YAG regenerative chirped pulse amplifier was developed. An average output power of 20 W was obtained at a repetition rate of 100 kHz with an output pulse width of 2 ps.