Kai Seger

Carbon nanotube mode-locked optically-pumped semiconductor disk laser

An optically pumped semiconductor disk laser was mode-locked for the first time by employing a single-walled carbon nanotube saturable absorber. Stable passive fundamental mode-locking was obtained at a repetition rate of 613 MHz with a pulse length of 1.23 ps. The mode-locked semiconductor disk laser in a compact geometry delivered a maximum average output power of 136 mW at 1074 nm.

Tunable Yb:KYW laser using a transversely chirped volume Bragg grating

We demonstrate a diode-pumped Yb:KYW laser, where the wavelength is controlled by a transversely chirped volume-Bragg-grating, also used as the laser output coupler. By translating the grating, the wavelength could be tuned from 997 nm to 1016 nm, with a spectral bandwidth of 13 GHz and a power up to 3.3 W. The laser cavity is simple and compact, and the tuning method is generally applicable to many other laser systems.

Highly efficient temporally stable narrow linewidth cryogenically cooled Yb-fiber laser

Cryogenic cooling is an effective way of increasing the efficiency in many solid-state lasers. In fiber lasers however, while the efficiency is increased, a reduced reabsorption in combination with reduced homogeneous broadening tends to broaden the linewidth, yielding a low spectral power density of the laser emission. In this work we lock a cryogenically-cooled Yb-doped fiber laser with a volume Bragg grating to overcome this problem and achieve a temporally stable narrow linewidth highly efficient laser. We extract 11.4-W of output power in spectral window of less than 0.4-nm with 14.5-W of launched pump light.

Carbon nanotube mode-locked vertical external-cavity surface-emitting laser

Mode-locking an optically pumped semiconductor disk laser has been demonstrated using low-loss saturable absorption containing a mixture of single-walled carbon nanotubes in PMM polymer. The modulator was fabricated by a simple spin-coating technique on fused silica substrate and was operating in transmission. Stable passive fundamental modelocking was obtained at a repetition rate of 613 MHz with a pulse length of 1.23 ps. The mode-locked semiconductor disk laser in a compact geometry delivered a maximum average output power of 136 mW at 1074 nm.