Transition Dipole, Charge Transfer, and Electron-hole Coherence in Two-photon Absorption: Visualizations with Two Dimensional Site and Three Dimensional Cube Representations

The photo-polymerization induced by Two-Photon Absorption (TPA) is tightly confined in the focus because the efficiency of TPA is proportional to the square of intensity. Three-dimensional (3D) micro-fabrication can be achieved by controlling the movement of the focus. Based on this theory, a system for 3D-micro-fabrication with femtosecond laser is proposed. The system consists of a laser system, a microscope system, a real-time detection system and a 3D-movement system, etc. The precision of micro-machining reaches a level down to 700nm linewidth. The line width was inversely proportional to the fabrication speed, but proportional to laser power and NA. The experiment results were simulated, beam waist of 0.413μm and TPA cross section of 2×10-54cm4s was obtained. While we tried to optimize parameters, we also did some research about its applications. With TPA photo-polymerization by means of our experimental system, 3D photonic crystal of wood-pile structure twelve layers and photonic crystal fiber are manufactured. These results proved that the micro-fabrication system of TPA can not only obtain the resolution down to sub-micron level, but also realize real 3D micro-fabrication.

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Theoretical studies on the one- and two-photon absorption of tetrabenzoporphyrins and phthalocyanines

Canadian Journal of Chemistry ◽

10.1139/v03-175 ◽

2004 ◽

Vol 82 (1) ◽

pp. 19-26 ◽

Cited By ~ 16

Author(s):

Xin Zhou ◽

Ai-Min Ren ◽

Ji-Kang Feng ◽

Xiao-Juan Liu

Keyword(s):

Dipole Moment ◽

Cross Sections ◽

Density Functional ◽

Transition Dipole Moment ◽

Photon Absorption ◽

Transition Dipole ◽

Two Photon Absorption ◽

Two Photon ◽

Order Of Magnitude ◽

The One

The one-photon absorption (OPA) properties of tetrabenzoporphyrins (TBPs) and phthalocyanines (Pcs) were studied using the semiempirical ZINDO method and time-dependent density functional theory (TDDFT), respectively. The compared results confirmed that the semiempirical ZINDO method was reasonably reliable when calculating the OPA of tetrabenzoporphyrins and phthalocyanines. On the basis of the OPA properties obtained from the ZINDO method, two-photon absorption (TPA) properties of two series of molecules were investigated, using ZINDO and sum-over-states (SOS) methods. The results showed that the TPA cross-sections of all molecules were in the range of 220.6 × 1050 345.9 × 1050 cm4·s·photon1, which were in the same order of magnitude as the values reported in the literature. The relatively larger δ(ω) value for Pcs with respect to that for corresponding TBPs originates from larger intramolecular charge transfer, which can be characterized by the difference of dipole moment between S0 and S1 and the transition dipole moment between S1 and S5.Key words: two-photon absorption, ZINDO, sum-over-states, tetrabenzoporphyrin, phthalocyanines.

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Novel A–(π–D–π–A)1–3 branched fluorophores displaying high two-photon absorption

RSC Advances ◽

10.1039/c6ra02733d ◽

2016 ◽

Vol 6 (52) ◽

pp. 46853-46863 ◽

Cited By ~ 4

Author(s):

Zhi-Bin Cai ◽

Hai-Min Shen ◽

Mao Zhou ◽

Sheng-Li Li ◽

Yu-Peng Tian

Keyword(s):

Charge Transfer ◽

Photon Absorption ◽

Two Photon Absorption ◽

Two Photon ◽

End Groups

Novel A–(π–D–π–A)3 compounds bearing pyridine end groups are apparently effective in achieving large two-photon responses owing to strong charge transfer.

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Highly sensitive two-photon chromophores applied to three-dimensional lithographic microfabrication: design, synthesis and characterization towards two-photon absorption cross section

Journal of Materials Chemistry ◽

10.1039/b309023j ◽

2004 ◽

Vol 14 (1) ◽

pp. 75 ◽

Cited By ~ 34

Author(s):

Youmei Lu ◽

Fuyuki Hasegawa ◽

Takamichi Goto ◽

Satoshi Ohkuma ◽

Setsuko Fukuhara ◽

...

Keyword(s):

Cross Section ◽

Absorption Cross Section ◽

Three Dimensional ◽

Photon Absorption ◽

Synthesis And Characterization ◽

Absorption Cross ◽

Design Synthesis ◽

Two Photon Absorption ◽

Two Photon ◽

Highly Sensitive

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Tuning of Hyperpolarizability, One- and Two-Photon Absorption of D-A and D-A-A Type Intramolecular Charge Transfer Based Sensors

10.26434/chemrxiv.7869062 ◽

2019 ◽

Author(s):

Pralok K. Samanta ◽

Md Mehboob Alam ◽

Ramprasad Misra ◽

Swapan K. Pati

Keyword(s):

Charge Transfer ◽

Gas Phase ◽

Density Functional ◽

Intramolecular Charge Transfer ◽

Photon Absorption ◽

First Hyperpolarizability ◽

Two Photon Absorption ◽

Two Photon ◽

Nlo Response ◽

Donor Acceptor

Solvents play an important role in shaping the intramolecular charge transfer (ICT) properties of π-conjugated molecules, which in turn can affect their one-photon absorption (OPA) and two-photon absorption (TPA) as well as the static (hyper)polarizabilities. Here, we study the effect of solvent and donor-acceptor arrangement on linear and nonlinear optical (NLO) response properties of two novel ICT-based fluorescent sensors, one consisting of hemicyanine and dimethylaniline as electron withdrawing and donating groups (molecule 1), respectively and its boron-dipyrromethene (BODIPY, molecule 2)-fused counterpart (molecule 3). Density functional theoretical (DFT) calculations using long-range corrected CAM-B3LYP and M06-2X functionals, suitable for studying properties of ICT molecules, are employed to calculate the desired properties. The dipole moment (µ) as well as the total first hyperpolarizability (βtotal) of the studied molecules in the gas phase is dominantly dictated by the component in the direction of charge transfer. The ratios of vector component of first hyperpolarizability (βvec) to βtotal also reveal unidirectional charge transfer process. The properties of the medium significantly affect the OPA, hyperpolarizability and TPA properties of the studied molecules. Time dependent DFT (TDDFT) calculations suggest interchanging between two lowest excited states of molecule 3 from the gas phase to salvation. The direction of charge polarization and dominant transitions among molecular orbitals involved in the OPA and TPA processes are studied. The results presented are expected to be useful in tuning the NLO response of many ICT-based chromophores, especially those with BODIPY acceptors.

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