Seminario Fisica de Partículas
Antimateria en el Cine & en Ciencia
Dr.Marco Aurelio Diaz, PUC
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Seminario Optica Cuantica
A new method for unique phase retrieval of ultrafast optical fields
Dr. Birger Seifert, PUC
Interferometric and noninterferometric methods have been developed for the full characterization of ultrashort optical signals as complex electric fields. While the spectral phase interferometry for direct electric field reconstruction (SPIDER) or measurement of electric field by interferometric spectral trace observation (MEFISTO) as interferometric methods allow field reconstruction by algebraic inversion algorithms, noninterferometric spectrographic techniques such as frequency-resolved optical gating (FROG) or temporal analysis of spectral components (TASC) rely on the solution of a phase-retrieval problem. Ultrashort pulses with well-separated frequency components cannot be recovered by any of these self-referenced methods (including SPIDER and MEFISTO) due to relative-phase ambiguities.Therefore a self-referencing technique for measuring amplitude and phase of ultrashort laser pulses is presented. In contrast to the other methods the relative-phase ambiguities do not appear. Thus, one can characterize ultrashort pulses with well-separated frequency components. The relative-phase ambiguities can be avoided by the use of a cross-correlation technique with two independent laser pulses. Further a new realtime phase-retrieval algorithm that reconstructs both pulses fast and uniquely is demonstrated experimentally.