Negatively chirped, self-compressing supercontinuum generation by ghost pulses

Abstract

Abstract Supercontinuum generation is an enabling technology for a host of intriguing applications such as tuneable ultra-fast light sources, ultra-short pulse generation, etc. It is governed by self-phase modulation, in which new frequencies are created at the leading and trailing edge of the light pulse with lower and higher frequencies, respectively. This spectral broadening is accompanied by positive chirp, opening the possibility to compress the pulse to a shorter duration by adding negative chirp. However, in many cases – e.g. in the ultraviolet spectral range - it is very difficult to introduce well-controlled negative chirp. Here, we present a solution to this problem, the first negatively chirped supercontinuum generation driven by ghost pulses. Ghost pulses have properties of real light pulses and are imprinted on longer carrier pulses with inverted intensity. Flipping the intensity, enables negatively chirped supercontinuum in the normal dispersion regime. With support from simulations, we have experimentally created and characterized ghost pulses, and demonstrated creation of a negatively chirped supercontinuum. We present a first application by a self-compressing non-collinear optical parametric amplifier. Our approach adds a new item to the toolbox of ultrafast technology enabling pulse compression for difficult cases where classical chirp management is not a viable option.