TY - JOUR A1 - Fiehler, Torben A1 - Saraceno, Clara A1 - Steinmeyer, Günter A1 - Wittrock, Ulrich T1 - Pitfall in autocorrelation measurements of laser radiation T2 - Optics Express N2 - Spectrally broad laser radiation from continuous wave (cw) lasers can exhibit second-order autocorrelation traces virtually indistinguishable from those of mode-locked lasers. Consequently, based only on autocorrelations, one might erroneously conclude that a cw laser is mode-locked. This pitfall in interpretation can be avoided by carefully characterizing radio frequency transients and spectra. However, optoelectronics are often too slow for lasers with an axial mode spacing in the multi-GHz range. Carefully evaluated autocorrelations then remain the last resort for validating mode locking. We demonstrate in detail what needs to be observed. We compare autocorrelation measurements and calculations of a mode-locked titanium-sapphire (Ti:Sa) laser with 76 MHz repetition rate and a spectrally broad monolithic cw Ti:Sa laser and devise a new, additional measurement to safeguard against misinterpretation of their autocorrelations. KW - Ti:Sa laser KW - autocorrelation KW - ultrafast lasers KW - pulse characterization Y1 - 2024 UR - https://www.hb.fh-muenster.de/opus4/frontdoor/index/index/docId/18427 UR - https://nbn-resolving.org/urn:nbn:de:hbz:836-opus-184276 UR - https://opg.optica.org/oe/fulltext.cfm?uri=oe-32-21-36811&id=560143 SN - 1094-4087 VL - 32 IS - 21 SP - 36811 EP - 36823 ER -