Abstract

Ultra-broadband light generation is one of the most novel nonlinear optical processes to have emerged over the last few years. With H₂ gas as the nonlinear medium, we predicted that, around 50 distinct frequencies of comparable energy may be generated [1]. In air, beams containing around 150 waves may be attained [2]. Such bandwidths are generated by resonantly driving a rotational Raman transition using symmetric two-colour pumping (input pulses with roughly equal intensity and shape) [1,2]. For configurations with resonant pump beams, we found that bandwidth was optimised by adjusting the level of normalised dispersion. A maximum in the bandwidth generated thus defined an optimal level of dispersion. Recently, we showed that this feature can be quantified in terms of an optimum level of gain suppression in the system [2].

© 1998 IEEE