Diode-pumped, high-average-power femtosecond Cr^3+:LiCAF laser

Abstract

We demonstrate a high-average-power continuous wave (cw) and cw mode-locked Cr3+ :LiCAF laser pumped by broad-area laser diodes. In cw lasing experiments, up to 580 mW of output was obtained with 4.35 W of incident pump. A semiconductor saturable absorber mirror was used to initiate stable, self-starting, mode locking. In the cw mode-locked regime, the Cr3+ :LiCAF laser produced nearly transform-limited, 67 fs long pulses near 800 nm with an average output power of 300 mW. The pulse repetition rate was 120 MHz, with a pulse energy of 2.5 nJ.

Generation of 15 nJ pulses from a highly efficient, low-cost multipass-cavity Cr^3+:LiCAF laser

“…:LiSGaF can be directly diode-pumped near 650 nm and enable the development of low-cost and highly efficient lasers operating near 800 nm [1][2][3][4][5][6][7][8][9][10][11]. Furthermore, the broad gain bandwidths of these media enable the generation of pulses as short as 10 fs [5,7].…”

“…Furthermore, the broad gain bandwidths of these media enable the generation of pulses as short as 10 fs [5,7]. Possible laser diode pump sources include diode arrays [4], broad-stripe single-emitter diodes [3,[7][8][9]11] as well as single transverse-mode diodes [6,10,11]. The peak powers obtainable from colquiriite media can be increased by scaling the output energy and/or reducing the pulsewidths.…”

“…We recently reported the generation of 67-fs pulses with energies and peak powers up to 2.5 nJ and ∼37 kW, respectively, from a Cr 3+ :LiCAF laser pumped by five 1-W broad-stripe diodes [9]. Using four, low-cost, single-mode pump diodes with a total absorbed power of 570 mW, 72-fs pulses were generated at a repetition rate of 127 MHz, corresponding to pulse energies of 1.4 nJ and peak powers of ∼19.5 kW [10].…”

“…Although higher peak powers can be obtained with multimode diode pumping [4,9], single mode pumping has the advantages of lower cost, better matching between pump and laser modes, significantly lower lasing thresholds, reduced thermal effects and higher efficiency [10,11]. For example, mode-locked optical-to-optical conversion efficiencies of ∼28% have been demonstrated with single-mode diode pumping [10], whereas only 6% and 7.5% efficiency could be obtained with arrays [4], and broad-stripe single-emitter diodes, respectively [9].…”

“…For example, mode-locked optical-to-optical conversion efficiencies of ∼28% have been demonstrated with single-mode diode pumping [10], whereas only 6% and 7.5% efficiency could be obtained with arrays [4], and broad-stripe single-emitter diodes, respectively [9]. Furthermore, for single mode diode pumping, no cooling is needed for the pump diodes or laser crystal, enabling compact and portable systems.…”