Nonlinear optical spectrum of diamond at femtosecond regime.

Although diamond photonics has driven considerable interest and useful applications, as shown in frequency generation devices and single photon emitters, fundamental studies on the third-order optical nonlinearities of diamond are still scarce, stalling the development of an integrated platform for nonlinear and quantum optics. The purpose of this paper is to contribute to those studies by measuring the spectra of two-photon absorption coefficient (β) and the nonlinear index of refraction (n) of diamond using femtosecond laser pulses, in a wide spectral range. These measurements show the magnitude of β increasing from 0.