A thin disk laser (TDL) invented in Germany in 1992 is a variant of a traditional disk laser conceived at General Electric in 1965. Using modern diode pumping and Yb:YAG crystal, the TDL was commercialized by Trumpf (and others) and it became a successful workhorse in many industrial applications requiring continuous wave (CW) laser source. One thing the TDL is NOT good at is pulsed operation requiring significant energy storage such as in amplification of femtosecond pulses to high (Joule-class) energies. This is because, as the name indicates, it uses a very thin laser disk (down to about 100 microns). The resulting low volume of the laser disk (about 1/100 of a cubic centimeter) simply cannot store much optical energy.
A far more suitable device for amplification of femtosecond (ultrashort) pulses to high energies at high-average power (kW-class) is the edge-pumped disk laser (EPDL) developed by Aqwest with the support by DARPA and the US Army ARDEC. EPDL has all the goodness of a disk laser – low susceptibility to deleterious thermal lensing and stress birefringence – exploited by the TDL while also offering 10’s of Joules of optical storage capacity. In addition, EPDL offers near diffraction-limited beam quality – something the TDL never quite attained – as well as much simpler and far more compact packaging. In the summer of 2013, Aqwest demonstrated a gain of 30 in kW-class EPDL amplifier. We target a gain of 100 for 2014. These results make the EDPL a number 1 choice for a high-average power amplifier for ultrashort pulse lasers