1Institute of Modern Optics, Nankai University, Laboratory of Optoelectronics Information Science and Technology, EMC, Tianjin 300071
2Institute of Material Physics, Tianjin University of Technology, Tianjin 300191
Two-Photon Absorption Properties of Mn-Doped ZnS Quantum Dots
1Institute of Modern Optics, Nankai University, Laboratory of Optoelectronics Information Science and Technology, EMC, Tianjin 300071
2Institute of Material Physics, Tianjin University of Technology, Tianjin 300191
Abstract： We investigate the two-photon absorption and nonlinear refractive index properties of a quantum dot material based on ZnS nanocrystals doped with Mn isoelectronic impurities, using the Z-scan technique with 532\,nm picosecond laser pulses. The Mn-doped ZnS quantum dots have an average two-photon absorption cross section as high as 13600 Goeppert--Mayer units, which turn it into a very promising material for fluorescent label and imaging in biological samples. In addition, we also found that the two-photon absorption coefficient initially increases and then decreases with increasing pulse irradiance, which demonstrates the presence of the higher-order nonlinearity under the strong excitation.
2006, Vol. 23 
