Modelocking of a thin-disk laser with the frequency-doubling nonlinear-mirror technique

Abstract

We demonstrate a frequency-doubling nonlinear-mirror (NLM) modelocked thin-disk laser. This modelocking technique, composed of an intracavity second harmonic crystal in combination with a dichroic output coupler, offers robust operation decoupled from cavity stability (as in semiconductor saturable absorber mirror (SESAM) modelocking) combined with an ultrafast saturable loss and high modulation depth (as in Kerr-lens modelocking (KLM)). With our NLM diode-pumped Yb:YAG thin-disk laser we achieve 21 W of average power at 323-fs pulse duration, which is an order of magnitude shorter than the previously obtained duration with the same technique in bulk lasers. Using these first results, we present a theoretical model for the NLM technique, which accurately predicts its loss modulation properties and the shortest achievable pulse duration without relying on any fitting parameters. Based on this simulation, we expect that the NLM technique will enable thin-disk lasers with average power of more than 100 W, with potentially sub-200 fs pulses. This could potentially solve the pulse duration limitations with SESAM modelocked Yb:YAG thin-disk lasers without imposing strong cavity stability constraints such as in KLM.

Solid-state Mamyshev oscillator

“…The design rules presented in this paper can be applied to Mamyshev mode-locking of other solid-state platforms such as thin disk lasers that promise ever higher pulse energy and average power [36][37][38]. Recently, such cascaded quadratic nonlinearity in PPLN waveguide has been utilized to demonstrate supercontinuum generation with a spectrum that spans multiple octaves [39].…”

Discrete Similariton and Dissipative Soliton Modelocking for Energy Scaling Ultrafast Thin-Disk Laser Oscillators

“…This topic has recently received significant attention in the community, as it is well-known that even for soliton modelocking, higher modulation depths are desired to reach shortest pulses at high power [42]. Several directions are currently being explored [43], and we believe a potential route to achieve this could be the implementation of an all-reflective NPE.…”

Wavelength-Tunable Nonlinear Mirror Mode-Locked Laser Based on MgO-Doped Lithium Niobate

“…M1, M2, M3, and M4 form a z-type cavity and the length of the resonant cavity is 1.3 m. The size of MgO:LN is 5 mm × 5 mm × 5 mm (w × h × l), and the phase-matching angle of MgO:LN is cut to be θ = 79.2°, φ = 90°. To date, most of the studies on NLM have focused on a particular wavelength, such as laser sources around 1, 1.3, and 2 µm [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. However, tunable picosecond lasers with output powers at the watt level are also of interest.…”

“…The peak power of the output laser is commonly at the kilowatt level while a bulk laser crystal is utilized, as shown in Figure 1. Combined with a thin-disk (TD) laser crystal, NLM disk (TD) laser crystal, NLM could generate ultrafast lasers within several hundreds of femtoseconds and with peak powers up to 10 MW [23,24].…”