Two-step four-photon absorption

Gu, Bing; Ji, Wei

doi:10.1364/oe.16.010208

Cited by 23 publications

(19 citation statements)

References 41 publications

(37 reference statements)

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“…This model is similar to that used for threelevel two-step 4PA but includes simultaneously ESA from both excited singlet and triplet states. 14 The process of nonlinear absorption ͑NLA͒ in the system is described as follows. The system simultaneously absorbs three identical photons, promoting electrons from S 0 to S 1 .…”

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confidence: 99%

Theoretical and experimental studies of three-photon-induced excited-state absorption

Yang

et al. 2010

Applied Physics Letters

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We theoretically and experimentally study excited-state absorption ͑ESA͒ induced by three-photon absorption ͑3PA͒ under the excitation of ultrafast laser pulses. Based on five-level rate-equation theory, we obtain an analytical expression for the effective four-photon absorption coefficient that originates from both singlet-singlet ͑S-S͒ and triplet-triplet ͑T-T͒ ESA. We validate that the T-T ESA could be justifiably neglected in the femtosecond regime. Experimentally, we verify it in acetone solution of 2,4,5-trimethoxychalcone by performing femtosecond Z-scan measurements; at low excitation intensity, only 3PA is determined; and under the excitation of high intensity, however, we observe the concurrence of 3PA and 3PA-induced S-S ESA processes.

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Theoretical and experimental studies of three-photon-induced excited-state absorption

Yang

et al. 2010

Applied Physics Letters

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“…The complicated calculations of the electron inter-band excitation and relaxation are needed for the simulation of the absorption enhancement 41, 42 . However, instead of analysis complex equation system of electron concentration dynamics in the excited states, the simplified absorption model can be used 42 .…”

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confidence: 99%

Multi-photon absorption enhancement by dual-wavelength double-pulse laser irradiation for efficient dicing of sapphire wafers

Gedvilas

Mikšys

Berzinš

et al. 2017

Sci Rep

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The evidence of multi-photon absorption enhancement by the dual-wavelength double-pulse laser irradiation in transparent sapphire was demonstrated experimentally and explained theoretically for the first time. Two collinearly combined laser beams with the wavelengths of 1064 nm and 355 nm, inter-pulse delay of 0.1 ns, and pulse duration of 10 ps were used to induce intra-volume modifications in sapphire. The theoretical prediction of using a particular orientation angle of 15 degrees of the half-wave plate for the most efficient absorption of laser irradiation is in good agreement with the experimental data. The new innovative effect of multi-photon absorption enhancement by dual-wavelength double-pulse irradiation allowed utilisation of the laser energy up to four times more efficiently for initiation of internal modifications in sapphire. The new absorption enhancement effect has been used for efficient intra-volume dicing and singulation of transparent sapphire wafers. The dicing speed of 150 mm/s was achieved for the 430 μm thick sapphire wafer by using the laser power of 6.8 W at the repetition rate of 100 kHz. This method opens new opportunities for the manufacturers of the GaN-based light-emitting diodes by fast and precise separation of sapphire substrates.

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“…We name this process as DWA and Figure 1 illustrates an effective 3PA process of 2PA-induced ESA. In this case, the propagation equation of the pulse intensity is given by [16]:…”

Section: Theory and Fundamentalsmentioning

confidence: 99%

Dual wavelength multiphoton absorption

Alubaidy

Venkatakrishnan

Tan

2013

Designed Monomers and Polymers

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In this study, we report a new phenomenon of multiphoton polymerization induced by dual wavelength irradiation with femtosecond laser of 515 and 1030 nm. We demonstrated a spatial resolution of 1200 nm from a laser spot of 1020 nm diameter. This is a significant increase in the spatial resolution of about 33 and 58% than the two photon absorption (2PA) and the three photon absorption (3PA) processes, respectively. This increase is a direct result of the significant reduction in the "Blurry" effect that is caused by continuous photochemical reaction beyond the targeted area. This phenomenon may allow the fabrications of two-dimensional and three-dimensional components of very high resolution.

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Two-step four-photon absorption

Cited by 23 publications

References 41 publications

Theoretical and experimental studies of three-photon-induced excited-state absorption

Theoretical and experimental studies of three-photon-induced excited-state absorption

Multi-photon absorption enhancement by dual-wavelength double-pulse laser irradiation for efficient dicing of sapphire wafers

Dual wavelength multiphoton absorption

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