Electric-field-induced second harmonic generation in silicon dioxide

Abstract

Electric-field-induced second harmonic generation (EFISH) as a third order nonlinear process is of high practical interest for the realization of functional nonlinear structures. EFISH in materials with vanishing χ(2) and non-zero χ(3) offers huge potential, e.g., for background-free nonlinear electro-optical sampling. In this work, we have investigated SiO 2 as a potential EFISH material for such applications using DC-electric fields. We were able to observe significant second harmonic generation (SHG) in comparison to the background SHG signal. The fundamental excitation at 800 nm results in a SHG signal at 400 nm for high applied DC electric fields, which is a clear indication for EFISH. Additionally, we were are able to precisely model the EFISH signal using time-domain simulations. This numerical approach will be of great importance for efficiency enhancement and prove as a valuable tool for future device design.

Terahertz-induced polar state in quantum paraelectric SrTiO3

“…In centrosymmetric medium with m3m point group symmetry, the main contribution providing second harmonic generation has quadrupole nature [19,20]. If electric field, of either low or high frequency, is applied then the total nonlinear polarization is determined by two terms, quadru-poleP (2 ) Q , which is field independent, and electric-dipoleP (2 ) ED E THz , which is field dependent (the latter is called "electric-field induced SHG", EFISH [21], or "THz field induced SHG" [3], TFISH):…”

Giant electric field-induced second harmonic generation in polar skyrmions

“…Emerging SHG devices demand integratable materials in which nonlinear optical properties can preferably be tuned by an applied electric field to enable electrical modulation and/or reconfiguration functionalities. As mediated by a thirdorder nonlinear optical (χ ð3Þ ) process which imposes no restraints on crystal symmetries, electric field-induced second-harmonic generation (EFISH) has been studied for various materials, including optical crystals 7,8 , polymers 9 , (strain-free) silicon 10,11 , layered metal chalcogenides [12][13][14][15][16] and artificial photonic structures 17,18 . However, these materials in general exhibit weak effective χ ð2Þ susceptibilities (which is the product of the χ ð3Þ susceptibility and electric field) and low modulation depths (mostly a few percent per volt), limiting their applications.…”

Giant electric field-induced second harmonic generation in polar skyrmions

“…Emerging SHG devices demand integratable materials in which nonlinear optical properties can preferably be tuned by an applied electric field to enable electrical modulation and/or reconfiguration functionalities. As mediated by a third-order nonlinear optical (𝜒 (3) ) process which imposes no restraints on crystal symmetries, electric field-induced second harmonic generation (EFISH) has been studied for various materials, including optical crystals 7,8 , polymers 9 , (strain-free) silicon 10,11 , layered metal chalcogenides [12][13][14][15][16] and artificial photonic structures 17,18 . However, these materials in general exhibit weak effective 𝜒 (2) susceptibilities (which is the product of the 𝜒 (3) susceptibility and electric field) and low modulation depths (mostly a few percent per volt), limiting their applications.…”