<title>Chirped frequency-shifted light pulses from a photonic-crystal fiber for pump-probe nonlinear absorption spectroscopy of molecular aggregates</title>

Abstract

Photonic-crystal fibers provide efficient nonlinear-optical transformations of femtosecond Cr: forsterite laser pulses, delivering linearly chirped frequency-shifted broadband light pulses, optimized for pump-probe nonlinear absorption spectroscopy of molecular aggregates. The blue-shifted output of a photonic-crystal fiber with a spectrum stretching from 530 to 680 nm is used to probe one- and two-exciton bands of thiacarbocyanine J aggregates in a polymer film excited by femtosecond second-harmonic pulses of the Cr: forsterite laser.