TY - JOUR TI - Nonlinear absorption properties of the charge states of nitrogen-vacancy centers in nanodiamonds AB - We have conducted a study on the nonlinear absorption properties of nitrogen-vacancy color centers in processed nanodiamonds. Their two-photon (2P) spectra disclose distinguishable features for the two charge states in which the center exists. The 2P absorption cross section is found to be between 0.1 and 0.5 GM in the wavelength range between 800 and 1040 nm. In addition, the center demonstrates the feature of strong 2P absorption for its neutral charge state below 1000 nm excitation wavelength and predominant 2P absorption by the negative charge state above this wavelength. AU - Ivanov, Ivaylo P. AU - Li, Xiangping AU - Dolan, Philip R. AU - Gu, Min PB - OSA PY - 2013/04/15 JO - Opt. Lett. JF - Optics Letters JA - Opt. Lett. VL - 38 IS - 8 SP - 1358 EP - 1360 KW - Fluorescent and luminescent materials KW - Multiphoton processes KW - Nanomaterials UR - http://ol.osa.org/abstract.cfm?URI=ol-38-8-1358 ER -