Non-linear Sagnac interferometry for pump-probe dispersion spectroscopy G. Jundt, G. T. Purves, C. S. Adams and I. G. Hughes Eur. Phys. J. D, 27 3 (2003) 273-276 Published online: 16 September 2003 DOI: 10.1140/epjd/e2003-00275-5