Nhng tin b trong Quang hc, Quang ph vÃ ng dng VI ISSN 1859 - 4271

More documents

Recommendations

Info

Advances in Optics, Photonics, Spectroscopy & Applications VI ISSN 1859 - 4271N λ= 2.053ExactLFE-92b x( =κ∆sinθ )10-1-2-3-3 -2 -1 0 1 2 3b ( =κ∆cosθ )zFig. 2: Spatial dispersion diagram for the LFE-9 formulation with a N λ= 2.05IV. CONCLUSIONThe traditional FD-FD method requires a more than 10 points per wavelength sampling of thetime-harmonic EM wave field. As a result, the FD-FD matrix equation becomes too large formost 3D problems and in many cases for some complex 2D optical waveguide devices. Wepropose a new nine-point stencil based on local Fourier-Bessel expansion for the 2-D Helmholtzequation in a homogeneous medium. This would reduce the sampling density to a value close toNyquist-Shannon spatial sampling of two points per wavelength.V. ACKNOWLEDGMENTSWe are grateful to the support by the Ministry of Education, Taiwan, under the Aim-for-the-Top University Plan.REFERENCES[1] Hung-Wen Chang and Sin-Yuan Mu, “Novel nine-point FD coefficients for two-dimensionalHelmholtz equation”, Cross Strait Four-Regional Radio Science and Wireless TechnologyConference, 2010, Hanan, China, Aug 2010.90
Những tiến bộ <strong>trong</strong> <strong>Quang</strong> học, <strong>Quang</strong> <strong>ph</strong>ổ và Ứng dụng VI ISSN 1859 - 4271ULTRAFAST PHOTO-DYNAMICS OF MALACHITE GREENIN LIQUID PHASELe Cong Nhan, Vo <strong>Quang</strong> MaiSaiGon University, 273 An Duong Vuong, District 5, Ho Chi Minh city, Viet NamE-mail: lcnhan@yahoo.frAbstract. Pump-probe broadband spectroscopy has been used to study the <strong>ph</strong>oto-dynamics ofMalachite Green (MG) in ethanol. The important results can be summarized as follows: determination*of lifetimes of S 2 , S 1 , S X , S 0 by a signal of induced absorption and stimulated emission. An analysisshows that the state relaxation involves two kinds of populations: hot molecules and meta-stableconfigurations.I. INTRODUCTIONTri<strong>ph</strong>enylmethane dyes (TPM) have been studied extensively for their molecular structures[1-3], their electronic states [4-6] and the <strong>ph</strong>oto-dynamic relaxation [7-9]. These molecules haveparticularly weak fluorescence in solvents of low viscosity (such as ethanol). The origin of thisdeactivation fluorescence is from the rotation (or torsion) of three <strong>ph</strong>enyl groups around a centralcarbon atom during relaxation [10-12]. The TPM can be classified into two groups according totheir molecular structure: symmetrical molecules and asymmetric molecules (Fig.1). Thesymmetrical molecules have two isomers and the asymmetric molecules have more two isomers[13-15].RR+Fig. 1. TPM structure {Malachite Green (MG) : R’= H, R=N(CH 3 ) 2 ; Brilliant Green (BG) : R’= H,R=N(C 2 H 5 ) 2 ; Crystal Violet (CV) : R’= R=N(CH 3 ) 2 ; Ethyl Violet (EV) : R’= R=N(C 2 H 5 ) 2 ; Parafuchsin(PF) : R’= R=N(CH 3 ) 2 }.In this work, we focus on the <strong>ph</strong>oto-dynamic properties of Malachite Green (MG) becausethis molecule represents an important model system for other TPM molecules and other ultra-fast<strong>ph</strong>oto-switches molecules. We have clarified the <strong>ph</strong>oto-dynamic of MG over the entire spectralrange from near UV to near infrared by pump-probe experience broadband. No<s<strong>trong</strong>>tin</s<strong>trong</strong>>g that thismolecule has been extensively studied by pump-probe spectroscopy [16] and fluorescence upconversion [12,17]. But there is still no complete study of the entire spectral range mentioned.R’91
Page 2 and 3:
Advances in Optics, Photonics, Spec
Page 4 and 5:
Advances in Optics, Photonics, Spec
Page 7 and 8:
Những tiến bộ trong</
Page 9 and 10:
Page 11 and 12:
Page 13 and 14:
Page 15 and 16:
Page 17 and 18:
Page 19 and 20:
Page 21 and 22:
Page 23 and 24:
Page 25 and 26:
Page 27 and 28:
Page 29 and 30:
Page 31 and 32:
Page 33 and 34:
Page 35 and 36:
Page 37 and 38:
Page 39 and 40:
Page 41 and 42:
Page 43 and 44:
Page 45 and 46:
Page 47 and 48:
Page 49 and 50:
Page 51 and 52: Những tiến bộ trong</
Page 101: Những tiến bộ trong</
Page 153 and 154:
Page 155 and 156:
Page 157 and 158:
Page 159:
show all

Nhng tin b trong Quang hc, Quang ph vÃ ng dng VI ISSN 1859 - 4271

Create successful ePaper yourself

Delete template?

Save as template?