scholarly journals An investigation on the second-order nonlinear optical response of cationic bipyridine or phenanthroline iridium(iii) complexes bearing cyclometallated 2-phenylpyridines with a triphenylamine substituent

2018 ◽  
Vol 47 (25) ◽  
pp. 8292-8300 ◽  
Author(s):  
Claus Hierlinger ◽  
David B. Cordes ◽  
Alexandra M. Z. Slawin ◽  
Alessia Colombo ◽  
Claudia Dragonetti ◽  
...  

A novel cationic Ir(iii) complex, characterized by a large NLO response, can be incorporated into a polymeric film leading to a good second-harmonic generation.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rabindra Biswas ◽  
Medha Dandu ◽  
Asish Prosad ◽  
Sarthak Das ◽  
Sruti Menon ◽  
...  

AbstractWe report strong second-harmonic generation (SHG) from 2H polytype of multilayer Tin diselenide (SnSe2) for fundamental excitation close to the indirect band-edge in the absence of excitonic resonances. Comparison of SHG and Raman spectra from exfoliated SnSe2 flakes of different polytypes shows strong (negligible) SHG and Raman Eg mode at 109 cm−1 (119 cm−1), consistent with 2H (1T) polytypes. The difference between the A1g–Eg Raman peak positions is found to exhibit significant thickness dependent for the 1T form, which is found to be absent for the 2H form. The observed thickness dependence of SHG with rapid oscillations in signal strength for small changes in flake thickness are in good agreement with a nonlinear wave propagation model considering nonlinear polarization with alternating sign from each monolayer. The nonlinear optical susceptibility extracted from SHG signal comparison with standard quartz samples for 1040 nm excitation is found to be more than 4-times higher than that at 1550 nm. This enhanced nonlinear response at 1040 nm is attributed to the enhanced nonlinear optical response for fundamental excitation close to the indirect band-edge. We also study SHG from heterostructures of monolayer MoS2/multilayer SnSe2 which allows us to unambiguously compare the nonlinear optical response of SnSe2 with MoS2. We find the SHG signal and any interference effect in the overlap region to be dominated by the SnSe2 layer for the excitation wavelengths considered. The comparison of SHG from SnSe2 and MoS2 underscores that the choice of the 2D material for a particular nonlinear optical application is contextual on the wavelength range of interest and its optical properties at those wavelengths. The present works further highlights the usefulness of near band-edge enhancement of nonlinear processes in emerging 2D materials towards realizing useful nanophotonic devices.


Author(s):  
Bingheng Ji ◽  
Elizabeth Guderjahn ◽  
Kui Wu ◽  
Tajamul Hussain Syed ◽  
Wei Wei ◽  
...  

Pb3P2S8 was structurally characterized three decades ago with a second harmonic generation response reported. In this work, Pb3P2S8 was revisited to investigate its electronic structure via DFT calculations and optical...


1996 ◽  
Vol 05 (02) ◽  
pp. 189-204 ◽  
Author(s):  
S. HORINOUCHI ◽  
H. IMAI ◽  
H. YAMASAKI ◽  
K. FUKAO ◽  
G.J. ZHANG ◽  
...  

Phase-matched blue second harmonic generation was observed in a corona-poled Corning 7059 glass film waveguide. The induced quadratic optical nonlinearity was examined by second harmonic generation with a time dependent decay for multi-complex of SiO 2, BaO,B 2 O 3 and/or Al 2 O 3. Glass films with every possible combination of composition were fabricated and examined, The glass composition of SiO 2- BaO-B 2 O 3 and/or SiO 2- BaO-Al 2 O 3 was found to play effective roles in maintaining the induced second order nonlinearity for a longer period of time. This is supposed to be related to distributed traps which come from complex of the glass components.


2021 ◽  
Vol 3 (6) ◽  
pp. 36-46
Author(s):  
Donald C. Boone

This research will examine the computational methods to calculate the nonlinear optical process of second harmonic generation (SHG) that will be hypothesized to be present during lithium ion insertion into silicon nanowires. First it will be determined whether the medium in which SHG is conveyed is non-centrosymmetric or whether the medium is inversion symmetric where SHG as a part of the second-order nonlinear optical phenomenon does not exist. It will be demonstrated that the main interaction that determines SHG is multiphoton absorption on lithium ions. The quantum harmonic oscillator (QHO) is used as the background that generates coherent states for electrons and photons that transverse the length of the silicon nanowire. The matrix elements of the Hamiltonian which represents the energy of the system will be used to calculate the probability density of second-order nonlinear optical interactions which includes collectively SHG, sum-frequency generation (SFG) and difference-frequency generation (DFG). As a result, it will be seen that at varies concentrations of lithium ions (Li+) within the crystallized silicon (c-Si) matrix the second-order nonlinear optical process has probabilities substantial enough to create second harmonic generation that could possibly be used for such applications as second harmonic imaging microscopy.


1999 ◽  
Vol 579 ◽  
Author(s):  
Sergey N. Rashkeev ◽  
Walter R. L. Lambrecht

ABSTRACTWe present our implementation of the length-gauge formalism of Sipe and coworkers (Phys. Rev. B 48, 11705 (1993); ibid 52, 14636 (1995)) using the linearized muffin-tin orbital (LMTO) method and discuss its application to the calculation of second order response functions. The importance of gap corrections beyond LDA is discussed. As primary application, we discuss the second harmonic generation (SHG) coefficients of the SiC polytypes and of the chalcopyrites of both the II-IV-V2 and I-III-VI2 families. These examples illustrate the relation of the second order response function to the modification of the crystal structure and chemical substitutions.


2013 ◽  
Vol 12 (02) ◽  
pp. 1250118 ◽  
Author(s):  
JING WEI ◽  
JIN-YUN WANG ◽  
MIN-YI ZHANG ◽  
GUO-LIANG CHAI ◽  
CHEN-SHENG LIN ◽  
...  

The second harmonic generation (SHG) hyperpolarizabilities of phenylalanine and homopolypeptides are investigated by configuration interaction among singly excited configurations (CIS) technique combined with the sum-over-states (SOS) method. The geometries of peptides containing phenylalanine ( Phe )n(n = 1–8) are optimized by B3LYP/6-31g(d) method, and they form the special structures like β-sheet (a common protein secondary structure). It is found that the energy gaps of various peptides are reduced and the hyperpolarizabilities are increased with the peptide chains lengthened. We discuss the origin of the second-order nonlinear optical response in phenylalanine homopolypeptides and confirm that the π → π* transitions in the aromatic residue of phenylalanine make the most important contributions to the second-order polarizability. Our results strongly suggest that the hyperpolarizabilities are dominated from the propagation direction of peptide chains.


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