First comparison of electric field induced second harmonic of near-infrared femtosecond laser pulses in reflection and transmission generated from Si/SiO2 interfaces of a silicon membrane
- 121 Downloads
For the first time electric field induced second harmonic (EFISH) generation of femtosecond (fs) laser pulses (λ=800 nm, τ=75±5 fs, rep. rate=80 MHz, Epulse≤10 nJ) is observed in transmission through a thin free-standing silicon (Si) membrane of 10-μm thickness and compared to the well-known EFISH results in reflection by use of the z-scan technique. EFISH in reflection and transmission unequivocally originate from the front and rear Si/SiO2 interfaces, respectively, with SiO2 being the natural oxide on the Si surfaces. Frequency conversion is enhanced by photoinduced electric fields across the Si/SiO2 interfaces caused by charge-carrier injection from Si into the oxide. The z-scan results and time-dependent measurements allow comparison of the EFISH signal amplitudes and time constants detected in transmission and reflection, demonstrating the need for further investigation.
- 17.R. Hull, Properties of Crystalline Silicon (INSPEC, London, 1999) Google Scholar
- 19.E.D. Palik, G. Ghosh, Handbook of Optical Constants of Solids (Academic Press, San Diego, 1998) Google Scholar
- 20.P.W. Milonni, J.H. Eberly, Lasers (Wiley, New York, 1988) Google Scholar
- 21.G.S. He, S.H. Liu, Physics of Nonlinear Optics (World Scientific, Singapore, 1999) Google Scholar