Kerr nonlinearity and multi-photon absorption in germanium at mid-infrared wavelengths
Abstract
Multiphoton absorption coefficients and nonlinear refractive indices of germanium in the near and mid-infrared (2–5 μm) are reported. The nonlinear coefficients are measured by open and closed aperture Z-scan with 150 fs pulses at a repetition rate of 1 kHz. The nonlinear refractive index of Ge has a peak value of 9.1×10−5cm2/GW at a wavelength of 3 μm. The effect of free electrons generated by multiphoton absorption is discussed by investigating the variation of multiphoton absorption coefficients at different input powers. Kramers-Kronig relations are also discussed with regard to the relationship between nonlinear refractive index and two photon absorption coefficient.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Aug 28, 2017
- Source ID
- 10.1063/1.4990590
Entities
People
- Anu Agarwal
- B.-u. Sohn
- Corentin Monmeyran
- D. T. H. Tan
- L. C. Kimerling
Organizations
- Air Force Office of Scientific Research
- Defense Threat Reduction Agency
- Massachusetts Institute of Technology
- National Research Foundation