Powerful 67 fs Kerr-lens mode-locked prismless Yb:KGW oscillator

Abstract

Abstract:We report on the generation of 67 fs pulses from a diode pumped Kerr-lens mode-locked Yb:KGW bulk laser. The average output power reached 3 W, corresponding to >38 nJ of pulse energy and >570 kW of peak power. The mode locking was initiated by a semiconductor saturable absorber. To the best of our knowledge, this is the highest average output power produced to date from Yb-ion based bulk lasers with such a short pulse duration.

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

“…Compared to our previous results of a KLAS modelocked Yb:KGW laser with a QD-SESAM [7], the generated pulse width was significantly reduced from 90 fs (FWHM=12.5 nm) to 56 fs (FWHM=20.5 nm) by decreasing the net-GVD from −4400 fs 2 to −3200 fs 2 , respectively. Our results also showed an enhancement in terms of a pulse duration compared to the previously reported KLAS mode-locked Yb:KGW laser based on a QW-SESAM, where 67 fs pulses with 3 W of output power were generated [6]. We believe that this can be explained by the increased level of SPM due to a longer crystal as well as lower output coupling.…”

“…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].…”

“…On the other hand, the Kerr-lens mode locking technique (KLM) enables one to generate shorter pulses due to its inherently fast saturable absorption-like effect, but it requires careful design procedure and does not usually offer self-starting oscillation [18]. A combination of these two techniques (termed KLAS: Kerr-lens and saturable absorber) can provide a mechanism that benefits from the self-starting operation provided by SESAM as well as the fast loss modulation and broadband operation of the KLM lasers [5,6]. Recently, we reported on the development of a high power sub-100 femtosecond KLAS mode-locked laser based on an InGaAs quantum-dot SESAM (QD-SESAM) [7] as an alternative approach to the widely used quantum-well SESAMs [5,6].…”

“…A combination of these two techniques (termed KLAS: Kerr-lens and saturable absorber) can provide a mechanism that benefits from the self-starting operation provided by SESAM as well as the fast loss modulation and broadband operation of the KLM lasers [5,6]. Recently, we reported on the development of a high power sub-100 femtosecond KLAS mode-locked laser based on an InGaAs quantum-dot SESAM (QD-SESAM) [7] as an alternative approach to the widely used quantum-well SESAMs [5,6]. Such QDSESAMs exhibit sub-picosecond recovery time, low saturation fluence (10-25 μJ/cm 2 ), and broad-bandwidth operation.…”

High-power, efficient, semiconductor saturable absorber mode-locked Yb:KGW bulk laser

“…[13] was not self-starting at high output powers, while the optical-to-optical efficiencies in Refs. [14,15] were only 5%-10%.In this Letter, an experimental study of pure SESAM modelocked Yb:KGW bulk lasers, which demonstrate extremely stable operation with high output powers, short pulse duration, and high optical-to-optical efficiencies, is presented for different polarization states of light in the crystals. A pumping scheme with a specially designed pump mirror was used to avoid restrictions on the cavity's gain bandwidth introduced by a dichroic input mirror in traditional longitudinal pumping schemes.…”