Detection of the second harmonic generation from single CdTe quantum dots of ∼11.5 nm diameter enables us to obtain an absolute value for the nonlinear susceptibility π(2) of these nanoparticles as well as their dispersion properties. These measurements, complemented by ensemble hyper-Rayleigh scattering characterization, elucidate the role of quantum confinement in the second harmonic generation process. We show that, under similar excitation conditions, the π(2) of quantum dots can significantly exceed that of the corresponding bulk material. The results indicate that by careful choice of excitation wavelength and material, kilo-counts per second rates of second harmonic generation photons can be obtained from quantum dots with <10 nm diameters, making second harmonic scattering quantum dots a promising option for use as biolabels.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films