rong Xu

The characteristic fluorescence of the serum of cancer patients

Abstract The characteristic fluorescence of cancer patients serum is observed and the center of luminescence is suggested. The diagnosis of cancer by fluorescence method is compared to clinical methods.

Protoporphyrin IX fluorescence from the plasma of tumor-implanted mouse

Abstract MH134 mouse tumor cells were implanted in C3H/HeN mice and the metabolic level of protoporphyrin IX from the tumor-implanted mice was studied. The fluorescence intensity from the plasma of tumor-implanted mice was obtained during the tumor development and the spectral ratio was used to determine the stage. The experimental data of metabolic level was analyzed and fitted to a function L ( t )= L 0 + L max [1−(( t − T /2)/( T /2)) 2 ], which described the tumor development and may be used to estimate the stage of disease in the tumor-implanted mice.

Energy transfer from Mn to Tm ions in ZnS at high pressure

Abstract The interaction of Mn and Tm ions in ZnS at high pressure is systematically studied. We have found that the energy transfer probability between Mn and Tm increases with an increase in the pressure. We have also discussed in detail the experimental results.

Correlated study of luminescence with nonlinear absorption in CdS

Abstract Corresponding to the fast process in nonlinear absorption we have also found a fast process of luminescence by means of the equal pulse correlation method. This intimate relation between these two processes indicates that they occur simultaneously in the same origin. The excitonic luminescence in the neighborhood of this fast component luminescence in the frequency domain is studied in detail. We measured the excitonic luminescence spectrum of CdS at temperatures ranging from 70 K to 300 K under an excitation intensity of 1 MW cm -2 . As the temperature is increased the two emission bands Ex-LO and I (bound exciton emission) evolve into a broad band E at 70 K. This E band shifts to lower energy as the temperature is raised. The rate of shift of this E band is larger than that of the band gap. When the intensity of excitation is increased the E band also shifts to red. These phenomena are interpreted as the luminescence induced by exciton-electron scattering.

The vibrational relaxation processes in BeAl2O4:Cr3+

Abstract The vibrational relaxation processes in BeAl 2 O 4 :Cr 3+ were studied by analysing the rise time of luminescence which was found to be 100 ps when excited by 532 nm.

Absorptive optical bistability due to impurity nonlinearity in CdS:Cu

Abstract With the excitation of a ps pulse laser we found both the optical bistability and the multi-order bistability in CdS: Cu + crystals. The nonlinear response time is as fast as 150 ps, and the switching time of the second-order bistable loop approaches 80 ps. The technique of the degenerate four wave mixing (DFWM) has been used to investigate the optical nonlinearity related to the Cu + impurity. The third-order nonlinear susceptibility of χ (3) was measured to be 9 × 10 −9 esu.

Luminescence and relaxation of the excited states in covalent-linked tetratolylporphyrin-phthalocyanine

The feature of the charge transfer in the binary molecules of the covalently bound porphyrin-phthalocyanine has been investigated by using a technique of the nondegenerate four-wave mixing. The energy transfer from porphyrin to phthalocyanine is spectrally found. The relation between the charge transfer and the covalent-bond length is also discussed.

THE LUMINESCENCE OF HIGHLY EXCITED CDS

Abstract We measure the emission spectra of single crystal CdS from 10 6 W/cm 2 to 10 7 W/cm 2 excitation intensity at 4.2K, and observe a new luminescence peaking at 4910A after the excitation intensity increases to 1.0 X 10 7 W/cm 2 .

Optical nonlinearity due to increased absorption in CdS at room temperature

Abstract Two types of the increased absorption with increasing excitation intensity at room temperature were observed. The experimental results show the origin of the nonlinearity.

THE INTERACTION BETWEEN MN AND DIFFERENT SM CENTERS IN ZNS

Abstract Two kinds of Sm centers in ZnS are identified. The interactions between Mn and these two kinds of Sm are found different. In the emission spectra of ZnS:Mn, Sm appears a new sharp line (about 2 cm -1 ). It would come from the Mn-Sm associated center.