Thin-disk multipass amplifier delivering sub-400 fs pulses with excellent beam quality at an average power of 1 kW
André Loescher, Florian Bienert, Christoph Röcker, Thomas Graf, Martin Gorjan, Jürg Aus der Au, Marwan Abdou Ahmed
Abstract
We present an improved multipass amplifier design, enabling the amplification of ultrashort pulses with excellent beam quality to more than 1 kW of average output power. 260 fs short pulses at an average power of 105 W and a repetition rate of 1 MHz were directly amplified up to an average power of 1033 W. The pulse duration at this power level was measured to be 388 fs assuming a Gaussian temporal shape. This corresponds to a peak power of 2.5 GW. The power stability was measured to be 0.16% RMS over a duration of more than two hours at a sampling rate of 2 Hz. High beam quality is proven with measured values of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msubsup> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mtext>M</mml:mtext> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mtext>x</mml:mtext> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mtext>2</mml:mtext> </mml:mrow> </mml:msubsup> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mtext> = 1</mml:mtext> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mtext>.16</mml:mtext> </mml:mrow> </mml:math> in the horizontal and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msubsup> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mtext>M</mml:mtext> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mtext>y</mml:mtext> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mtext>2</mml:mtext> </mml:mrow> </mml:msubsup> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mtext> = 1</mml:mtext> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mtext>.19</mml:mtext> </mml:mrow> </mml:math> in the vertical plane according to ISO Standard 11146.