Photoacoustic calorimetry of femtosecond laser pulses
A.N. Iglakova1, V.K. Oshlakov1, L.V. Seleznev2, B.A. Tikhomirov1
1V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, 1, Academician Zuev square, Tomsk, 634021, Russia
2P.N. Lebedev Physical Institute of the Russian Academy of Science, 53 Leninskij Prospekt, 119991, Moscow, Russia
Keywords: terawatt femtosecond laser, measurement of the energy characteristics, photoacoustic receiver
Abstract
To measure the energy of femtosecond laser pulses (248, 744, and 800 · 10–9 m), a photoacoustic receiver with a black body (as an absorbent element) and a condenser microphone (as a converter) placed in the enclosed volume with gas were tested. The device allows measurements of the energy of UV and IR laser pulses over a wide dynamic range (more than 80 dB with MK 221 microphone). The pulse repetition rate is up to 15 Hz, pulse duration, from 20 · 10–15 to 100 · 10–9 s, the threshold sensitivity, 10–9 J. High sensitivity of the receiver provides reliable measurements of energy of terawatt femtosecond laser pulses in the main absorption channel of radiation passing through the rotating mirror with a reflection coefficient close to 100%.
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