Ultrafast Nonlinear Optics team

Mid-IR supercontinuum generation in an LIS crystal

The Ultrafast Nonlinear Optics (UNO) team focuses on nonlinear optics with ultrafast laser pulses on a femtosecond time scale.

About the team

In the Ultrafast Nonlinear Optics team we investigate nonlinear optical phenomena with ultrafast femtosecond pulses, where the excitation of temporal solitons in bulk media or optical waveguides and fibers allow achieving efficient frequency conversion, pulse compression and supercontinuum generation. Our main focus is solitons generated in quadratic nonlinear crystals through cascaded (phase-mismatched) frequency conversion processes. This gives access to a unique self-defocusing nonlinearity that has many advantages compared to traditional self-focusing four-wave mixing processes, in particular that it is inherently filament free. We are currently exploring new opportunities in the mid-IR range (2-20 micron) for supercontinuum generation and pulse compression of high energy pulses (in bulk crystals) or high-repetition rate low energy pulses (waveguides). We also investigate new hollow-core fibers for broadband handling, transmission and nonlinear interaction of near to mid-IR pulses in gas-filled fibers.


  1. First theoretical explanation of the nonlocal nature of ultrafast cascaded nonlinearities (Bache et al. OL 2007)
  2. First theoretical prediction of optical Cherenkov radiation in ultra-fast cascaded second-harmonic generation (Bache et al. PRA 2010)
  3. First experimental observation of filament-free soliton-induced octave-spanning supercontinuum using nonresonant defocusing cascaded nonlinearities (Zhou et al. PRL 2012)
  4. First noncritical (type 0) soliton compression experiment with defocusing cascaded nonlinearities (Zhou et al. PRL 2012)
  5. First experimental observation of resonant nonlocal response with defocusing cascaded nonlinearities (Zhou et al. PRA 2014)
  6. First experimental observation of octave-spanning supercontinuum generation in an unpoled quadratic nonlinear waveguide (Guo et al. OL 2015)
  7. First experimental observation of mid-IR optical Cherenkov radiation with defocusing cascaded nonlinearities (Zhou et al. OE 2015)

Team leader

Morten Bache
DTU Fotonik
+45 45 25 37 75