Third-order non-linearities are important because they allow control over light pulses in ubiquitous high-quality centro-symmetric materials like silicon and silica.Degenerate four-wave mixing provides a direct measur...Third-order non-linearities are important because they allow control over light pulses in ubiquitous high-quality centro-symmetric materials like silicon and silica.Degenerate four-wave mixing provides a direct measure of the third-order non-linear sheet susceptibility x^(3)(where L represents the material thickness)as well as technological possibilities such as optically gated detection and emission of photons.Using picosecond pulses from a free electron laser,we show that silicon doped with P or Bi has a value of x^(3)Lin the THz domain that is higher than that reported for any other material in any wavelength band.The immediate implication of our results is the efficient generation of intense coherent THz light via upconversion(also a x^(3)process),and they open the door to exploitation of nondegenerate mixing and optical nonlinearities beyond the perturbative regime.展开更多
基金We acknowledge financial support from the UK Engineering and Physical Sciences Research Council[ADDRFSS,Grant No.EP/M009564/1]the EPSRC National Research Facility,FELIX
文摘Third-order non-linearities are important because they allow control over light pulses in ubiquitous high-quality centro-symmetric materials like silicon and silica.Degenerate four-wave mixing provides a direct measure of the third-order non-linear sheet susceptibility x^(3)(where L represents the material thickness)as well as technological possibilities such as optically gated detection and emission of photons.Using picosecond pulses from a free electron laser,we show that silicon doped with P or Bi has a value of x^(3)Lin the THz domain that is higher than that reported for any other material in any wavelength band.The immediate implication of our results is the efficient generation of intense coherent THz light via upconversion(also a x^(3)process),and they open the door to exploitation of nondegenerate mixing and optical nonlinearities beyond the perturbative regime.
