Femtosecond Kerr-lens mode-locked Alexandrite laser

Abstract

The generation of 170 fs pulses at 755 nm from a Kerr-lens mode-locked Alexandrite laser was demonstrated. The laser was pumped at 532 nm and produced 780 mW of average output power with 9.8% of optical-to-optical efficiency. To the best of our knowledge, these are the shortest pulses that have been produced from a mode-locked Alexandrite laser to date.

Graphene mode-locked femtosecond Alexandrite laser

“…Furthermore, by utilizing the broad tuning range of the Alexandrite gain medium, several recent studies have focused on ultrashort pulse generation. In particular, Ghanbari et al reported the generation of femtosecond pulses from a Kerr-lens mode-locked (KLM) Alexandrite laser for the first time [18]. The same group later succeeded in producing 380 fs pulses at 775 nm by using an InP/InGaP quantum dot semiconductor saturable absorber mirror [19].…”

InP/InGaP quantum-dot SESAM mode-locked Alexandrite laser

“…The designed 5-mirror cavity was similar to the one previously used in the KLM experiments [16]. The Brewster-cut Pump C 532 nm…”

“…Furthermore, a diode-pumped Alexandrite laser was shown to produce >26 W of output power in the continuous wave regime [13] which significantly exceeds output from widely used Ti:sapphire lasers. Despite these advantages, femtosecond laser mode locking was demonstrated only recently and resulted in the generation of 170 fs long pulses from a Kerr-lens mode-locked (KLM) Alexandrite laser [16]. At the same time, passive mode locking with a semiconductor saturable absorber mirror (SESAM) is an effective method that is widely used with Nd-doped and Yb-doped gain media to produce ultrashort pulses [17][18][19][20][21][22][23][24] because it does not require critical cavity alignment that is needed in case of KLM lasers [25,26].…”

Temperature dependence of Alexandrite effective emission cross section and small signal gain over the 25-450 °C range

“…Over the last decade, the advancement of higher brightness laser and light-emitting diodes in the red spectral region, generated a renewed interest towards Alexandrite [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] and continuous-wave laser output powers above 25 W have already been achieved from compact diode-pumped systems [12]. Mode-locking of Alexandrite using Saturable Bragg Reflectors (SBRs) [26], Kerr-lensing [27,28], and graphene saturable absorbers [29] has also been demonstrated recently. Unlike simple laser systems such as Yb:YAG, Alexandrite has a complex energy level diagram ( Fig.…”

“…As a more specific example, over the last years, several groups have been working on the development of ultrashort pulse Alexandrite laser systems [26][27][28][29], which resulted in the generation of down to 70-fs long pulses with average output powers in the multi-mW to multi-100 mW range. Unfortunately, mode-locking is only demonstrated in systems pumped by complex green laser sources so far.…”