Higher-order nonlinearity of refractive index: The case of argon
Abstract
The nonlinear coefficients, n4, of the time-dependent refractive index for argon are calculated in the non-resonant optical regime. Second-order polynomial fitting of DC-Kerr, γ(2)(−ω; ω, 0, 0), electric field induced second harmonic generation (ESHG), γ(2)(−2ω; ω, ω, 0), and static second-order hyperpolarizability, γ(2)(0; 0, 0, 0), is performed using an auxiliary electric field approach to obtain the corresponding fourth-order optical properties. A number of basis sets are investigated for the fourth-order hyperpolarizability processes at 800 nm at coupled cluster singles and doubles level of theory, starting with the t-aug-cc-pV5Z basis set and expanding that basis set by adding diffuse functions and polarization functions. Comparison shows that the results obtained with the t-aug-cc-pV5Z basis are in very good agreement with the results obtained using the q-aug-cc-pV5Z, t-aug-cc-pV6Z, and q-aug-cc-pV6Z basis sets. To calculate the nonlinear refractive index n4, an approximate formula is suggested which expresses the related degenerate six-wave mixing coefficient, γ(4)(−ω; ω, −ω, ω, −ω, ω), in terms of the DC-Kerr, γ(4)(−ω; ω, 0, 0, 0, 0), ESHG, γ(4)(−2ω; ω, ω, 0, 0, 0), and the static fourth-order hyperpolarizability coefficients. The higher-order nonlinear refractive index n4 is found to be positive over the wavelengths 300 nm–2000 nm. In the infrared spectral range, the obtained values of n4 are in qualitative agreement with the results of Kramers-Kronig-based calculations.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jun 05, 2014
- Source ID
- 10.1063/1.4880716
Entities
People
- Dmitri A. Romanov
- Maryam Tarazkar
- Robert J Levis
Organizations
- Air Force Office of Scientific Research
- Defense Threat Reduction Agency
- Office of Naval Research
- Temple University