We report the use of starch as an ideal nonlinear medium with which to perform collinear frequency-resolved optical gating measurements of ultrashort pulses at the focal plane of a high-numerical-aperture (NA) lens. We achieved these measurements by simply sandwiching starch granules (suspended in water) between two coverslips and placing them within the focal plane of a high-NA lens. The natural nonlinear characteristics of starch allow the correct phase matching of pulses at the focal plane of a high-NA lens at different wavelengths. This elegant arrangement overcomes all the complexity and problems that were previously associated with pulse characterization within a multiphoton microscope.
© 2004 Optical Society of America
(100.5070) Image processing : Phase retrieval
(180.0180) Microscopy : Microscopy
(190.4400) Nonlinear optics : Nonlinear optics, materials
(190.4710) Nonlinear optics : Optical nonlinearities in organic materials
(320.7100) Ultrafast optics : Ultrafast measurements
Ivan Amat-Roldán, Iain G. Cormack, Pablo Loza-Alvarez, and David Artigas, "Starch-based second-harmonic-generated collinear frequency-resolved optical gating pulse characterization at the focal plane of a high-numerical-aperture lens," Opt. Lett. 29, 2282-2284 (2004)