BMI delivers terawatt, femtosecond amplifier
The National Laboratory for High Energy Physics (Tsukuba, Japan) has received the first of B.M. Industries (BMI, Evry, France) Alpha-10/C femtosecond Ti:sapphire laser amplifiers for use in an electron accelerator. The system, originally specified for 2 TW, is capable of producing more than 3.4-TW output power around 800 nm at a 10-H¥repetition rate. Pulse energy is greater than 240 mJ for a duration of less than 70 fs with a 15-nm input spectrum from a femtosecond oscillator. To kee¥from damaging system optics at such high power, large-size optics with high-damage-threshold coatings are used to reduce power density along with maintaining a smooth beam profile, with an M2 of roughly 1.4. Safety interlocks make sure the oscillator spectrum and central wavelength are stable, so pulse duration is not suddenly reduced, for example, producing a power spike. Another device checks that repetition rate is held constant for steady thermal loading. The next Alpha-10/Cs will be delivered to another customer in Japan by October and to one in Germany before the end of the year. A company spokesperson says it plans to improve the amplifier to reach pulse widths less than 50 fs with peak power close to 10 TW for a prospective, unnamed user.