title: Broadband sensitive pump-probe setup for ultrafast optical switching of photonic nanostructures and semiconductors.
abstract: We describe an ultrafast time resolved pump-probe spectroscopy setup aimed at studying the switching of nanophotonic structures. Both femtosecond pump and probe pulses can be independently tuned over broad frequency range between 3850 and 21,050 cm(-1). A broad pump scan range allows a large optical penetration depth, while a broad probe scan range is crucial to study strongly photonic crystals. A new data acquisition method allows for sensitive pump-probe measurements, and corrects for fluctuations in probe intensity and pump stray light. We observe a tenfold improvement of the precision of the setup compared to laser fluctuations, allowing a measurement accuracy of better than DeltaR=0.07% in a 1 s measurement time. Demonstrations of the improved technique are presented for a bulk Si wafer, a three-dimensional Si inverse opal photonic bandgap crystal, and z-scan measurements of the two-photon absorption coefficient of Si, GaAs, and the three-photon absorption coefficient of GaP in the infrared wavelength range.
authors: FOM Institute for Atomic and Molecular Physics (AMOLF), Kruislaan 407, 1098 SJ Amsterdam, The Netherlands.
authors: Tijmen G
authors: TG
authors: Euser
authors: Philip J
authors: PJ
authors: Harding
authors: Willem L
authors: WL
authors: Vos
mesh_terms: D000465:Algorithms; D001152:Arsenicals / Q000737:chemistry; D005708:Gallium / Q000737:chemistry; D007834:Lasers; D049329:Nanostructures; D055095:Optics and Photonics / Q000295:instrumentation*; D012666:Semiconductors / Q000295:instrumentation; D012825:Silicon / Q000737:chemistry; D013057:Spectrum Analysis / Q000295:instrumentation*; D013997:Time Factors
chemical_list: D001152:Arsenicals; D005708:Gallium; D012825:Silicon