32-fs Kerr-lens mode-locked Yb:CaGdAlO_4 oscillator optically pumped by a bright fiber laser

Abstract

In this study, we report on a pure Kerr-lens mode-locked Yb:CaGdAlO₄ oscillator optically pumped by a diffraction-limited fiber laser. At the repetition rate of 96 MHz, several configurations have been studied to achieve either pulse duration of 40 fs with average powers up to the watt level or shorter pulse duration down to 32 fs. To the best of our knowledge, this represents the shortest pulse duration ever achieved with an Yb-doped bulk material and the highest average power for sub-40-fs Kerr-lens mode-locked Yb-bulk oscillator.

Diode-pumped ultrafast Yb:KGW laser with 56 fs pulses and multi-100 kW peak power based on SESAM and Kerr-lens mode locking

“…For example, the generation of 94 fs pulses with 12.5 W of average output power with SESAM mode locking was reported in [8]. Shorter pulses with a duration of 40 fs at lower output power of 1.1 W was also demonstrated in this crystal by Kerr-lens mode locking technique [9]. Another promising Yb-doped laser crystal for generating high power sub-100 fs pulses is Yb:CaF2 crystal with a thermal conductivity coefficient of 6 W/m/K and emission bandwidth of 30 nm [34,35].…”

“…The generation of 68 fs and 48 fs pulses with output powers of 2.3 W and 2.7 W using the Kerr-lens mode locking have been reported in [12] and [10], respectively. It should be noted that results presented in [9,10] and [12] were not obtained with directly diodepumped lasers which greatly reduces their overall efficiency and potential for further power scaling. Therefore, the use of commercially available laser diodes for direct diode pumping is a desired feature due to the reduced cost and complexity of the laser system.…”

“…The Yb-ion based laser oscillators are well suited for this task. The generation of watt-level sub-100 femtosecond laser pulses directly from Yb-doped bulk crystal lasers has been reported for Yb:KGW [5][6][7], Yb:CALGO [8,9], Yb:CaF2 [10][11][12] and Yb 3+ :Lu2O3 [13] gain media. Such a performance of a mode-locked laser is feasible owing to the propitious properties of Yb-ion crystals, including a fairly broad gain bandwidth, absorption properties suitable for a diode pumping, an absence of parasitic losses and a tolerable level of thermo-optical effects [14][15][16].…”

Kerr-Lens Mode-Locked Femtosecond Yb:GdYSiO5 Laser Directly Pumped by a Laser Diode

“…Until now, a number of Yb 3+ -doped laser materials have been developed to generate femtosecond pulses [3][4][5][6][7]. The shortest pulse duration reported thus far was 32 fs in a Yb:CaGdAlO4 oscillator optically pumped by a fiber laser [8]. Such femtosecond lasers in the 1 μm wavelength range may be a valuable alternative to Ti:sapphire lasers in many applications.…”

Thermo-optic characterization of Yb:CaGdAlO_4 laser crystal

“…The interest to Yb:CALGO is motivated by its beneficial spectroscopic and thermal properties [2,3], that allowed for realization of high-efficient and high-power bulk [4,5] and thin-disk lasers [6,7], as well as generation and amplification of ultrashort pulses [8][9][10][11][12][13][14] with pulse production as short as 32 fs [10]. However, Yb:CALGO demonstrate very particular thermal properties involving a strong anisotropy of its lattice.…”