Kerr lens mode-locked Yb:Lu₂O₃bulk ceramic oscillator pumped by a multimode laser diode

Abstract

We report Kerr lens mode-locking of a Yb:Lu 2 O 3 bulk ceramic oscillator with an output power of 1.83 W, a pulse duration of 135 fs at a repetition rate of 78 MHz, corresponding to a pulse energy of 23.5 nJ. Single-mode oscillation and Kerr lens mode-locking have been achieved with a special geometry using a multimode laser diode with a low brightness as a pump source. To the best of our knowledge, the obtained pulse energy is the highest in any mode-locked Yb:Lu 2 O 3 bulk ceramic oscillator.

Kerr-lens mode locking of a diode-pumped Yb:KGW laser using an additional intracavity Kerr medium

“…At the same time the Kerr-lens and SESAM mode-locked Yb:KGW lasers in [39,40] produced shorter pulses of 67 and 56 fs, respectively, probably due to the higher effective modulation depth resulting from the use of both techniques. As was mentioned earlier, the use of an additional Kerr medium as well as MM LD pumping has also been reported for the Yb:Lu 2 O 3 ceramic laser [21]. The laser system used a CaF 2 plate as the Kerr medium and the generation of 135 fs pulses with 1.83 W of average power was demonstrated based on the hard-aperture KLM technique.…”

“…It can be especially beneficial for the laser systems where an MM LD is used for pumping. The use of an additional Kerr medium has been investigated for bulk KLM lasers [19,[21][22][23][24][25][26][27][28][29][30][31]. Recently, high power KLM lasers with MM LD pumping and an enhanced Kerr effect have been reported for Yb:Lu 2 O 3 ceramic (135 fs, 1.83 W) [21] and Yb:CALYO lasers (68 fs, 1.5 W) [19].…”

“…The use of an additional Kerr medium has been investigated for bulk KLM lasers [19,[21][22][23][24][25][26][27][28][29][30][31]. Recently, high power KLM lasers with MM LD pumping and an enhanced Kerr effect have been reported for Yb:Lu 2 O 3 ceramic (135 fs, 1.83 W) [21] and Yb:CALYO lasers (68 fs, 1.5 W) [19]. For KLM thin-disk lasers, additional Kerr medium is a necessary part of the laser system owing to the small amount of the Kerr effect which can be induced by the thin laser medium [32][33][34].…”

Mode-locked Ti:sapphire laser oscillators pumped by wavelength-multiplexed laser diodes

“…To obtain better mode overlapping in the laser crystal for LD pumping with low beam quality, an additional nonlinear medium has been placed in the cavity, or concave mirrors with larger focal length and an additional intracavity plane mirror were used. 29,30) Recently, a spatially combined green LD (>10 W) delivered by a multimode fiber has become available. Assuming a 10 W green output from a 100-µm-diameter fiber core whose numerical aperture (NA) is 0.2, the power is still insufficient to obtain efficient Ti:sapphire lasing owing to a limited overlap efficiency.…”

7.6-W diode-pumped femtosecond Yb:KGW laser

“…[4,5] Lasers delivered directly from the oscillator with both femtosecond pulse and high output average power are more desirable for many applications. Yb-doped gain media such as Yb:KGd(WO 4 ) 2 (Yb:KGW), [6][7][8] Yb:CaYAlO 4 (Yb:CYA), [9] Yb:CaGdAlO 4 (Yb:CALGO), [10] Yb:Lu 2 O 3 , [11] and Yb:CaF 2 [12] have been used to generate watt-level femtosecond laser pulses. The highest average output power of 12.5 W was obtained from an 80-MHz Yb:CALGO oscillator with the pulse duration of 94 fs.…”