Reverse Saturable Absorption and Induced Thermal Effects in Chlorophyll ‘A’

1997 ◽  
Vol 479 ◽  
Author(s):  
J. M. Robertson ◽  
G. Bourhill
Keyword(s):  
Chlorophyll A ◽  
Thermal Effects ◽  
Transient Absorption ◽  
Measurement Techniques ◽  
Excited State Absorption ◽  
Transient Absorption Spectroscopy ◽  
Saturable Absorption ◽  
Reverse Saturable Absorption ◽  
Optical Effects ◽  
Nonlinear Optical Effects

AbstractThe nonlinear optical effects of chlorophyll ‘a’ have been determined using an array of measurement techniques. Regions of spectral interest exhibiting induced excited state absorption were identified with transient absorption spectroscopy measurements. At specific wavelengths within these regions, the dye was characterised using the Z-scan technique. Additional measurements were made to complement the latter results including a focused aperture experiment in which thermal defocusing and scattering mechanisms were identified.

Liquid Crystals for Fast Infrared Laser Switching and Optical Limiting Application

1997 ◽  
Vol 479 ◽  
Author(s):  
I. C. Khoo ◽  
M. V. Wood ◽  
Brett D. Guenther
Keyword(s):  
Excited State ◽  
Liquid Crystals ◽  
Chlorophyll A ◽  
Nonlinear Optical ◽  
Transient Absorption ◽  
Measurement Techniques ◽  
Excited State Absorption ◽  
Transient Absorption Spectroscopy ◽  
Optical Effects ◽  
Nonlinear Optical Effects

AbstractThe nonlinear optical effects of chlorophyll ‘a’ have been determined using an array of measurement techniques. Regions of spectral interest exhibiting induced excited state absorption were identified with transient absorption spectroscopy measurements. At specific wavelengths within these regions, the dye was characterised using the Z-scan technique. Additional measurements were made to complement the latter results including a focused aperture experiment in which thermal defocusing and scattering mechanisms were identified.

Femtosecond to Nanosecond Characterization of Optical Limiting Mechanisms in Power Limiting Liquids and Solids

1999 ◽  
Vol 597 ◽  
Author(s):  
A. Malko ◽  
S. Xu ◽  
H-L. Wang ◽  
R. Kohlman ◽  
L. Smilowitz ◽  
...  
Keyword(s):  
Solid State ◽  
High Performance ◽  
Transient Absorption ◽  
Visible Spectrum ◽  
Damage Threshold ◽  
Optical Limiting ◽  
Transient Absorption Spectroscopy ◽  
Saturable Absorption ◽  
Reverse Saturable Absorption ◽  
Femtosecond Transient Absorption

AbstractWe present our recent advances toward the development of high-performance solid-state optical limiting devices using reverse saturable absorption (RSA) dyes doped into optical host materials. Femtosecond transient absorption spectroscopy was employed to determine both the spectral regions of strong RSA, and the singlet-triplet excited-state dynamics. The optical limiting in the visible spectrum in both metallo-phthalocyanines and metallo-porphyrins is due to a combination of singlet and triplet RSA. Optical limiting performance was studied for RSA dyes in dual tandem limiters (both in solution and solid-state). Our best results in the solid-state yielded an attenuation of 400x, and a damage threshold of up to several mJ at f/5 focusing. The optical limiting at f/5 is further enhanced, particularly in the solid-state, by self-defocusing thermal nonlinearities.

Effects of extending the π-conjugation of the acetylide ligand on the photophysics and reverse saturable absorption of Pt(ii) bipyridine bisacetylide complexes

2016 ◽  
Vol 18 (41) ◽  
pp. 28674-28687 ◽  
Author(s):  
Taotao Lu ◽  
Chengzhe Wang ◽  
Levi Lystrom ◽  
Chengkui Pei ◽  
Svetlana Kilina ◽  
...  
Keyword(s):  
Excited State ◽  
Excited States ◽  
Substituent Effect ◽  
Excited State Absorption ◽  
Saturable Absorption ◽  
Reverse Saturable Absorption ◽  
Triplet Excited State ◽  
Near Ir ◽  
Terminal Substituent ◽  
Acetylide Ligand

Extending the acetylide ligand π-conjugation diminishes the terminal substituent effect on the lowest excited states, but expands the triplet excited-state absorption to the near-IR region.

Photophysics and reverse saturable absorption of cationic dinuclear iridium(iii) complexes bearing fluorenyl-tethered 2-(quinolin-2-yl)quinoxaline ligands

2021 ◽  
Author(s):  
Cuifen Lu ◽  
Taotao Lu ◽  
Peng Cui ◽  
Svetlana Kilina ◽  
Wenfang Sun
Keyword(s):  
Excited State ◽  
Excited State Absorption ◽  
Saturable Absorption ◽  
Reverse Saturable Absorption ◽  
Triplet Excited State ◽  
532 Nm

Dinuclear Ir(iii) complexes tethered by fluorenyl motif exhibited weak 1,3MLCT/1,3LLCT absorption at >500 nm, dual phosphorescence, broad triplet excited-state absorption, and reverse saturable absorption at 532 nm.

Extending the Bandwidth of Reverse Saturable Absorption in Platinum Complexes Using Two-Photon-Initiated Excited-State Absorption

2013 ◽  
Vol 5 (3) ◽  
pp. 565-572 ◽  
Author(s):  
Bingguang Zhang ◽  
Yunjing Li ◽  
Rui Liu ◽  
Timothy M. Pritchett ◽  
Joy E. Haley ◽  
...  
Keyword(s):  
Excited State ◽  
Excited State Absorption ◽  
Platinum Complexes ◽  
Saturable Absorption ◽  
Reverse Saturable Absorption ◽  
Two Photon

scholarly journals Broadband Visible Nonlinear Absorption and Ultrafast Dynamics of the Ti3C2 Nanosheet

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2544
Author(s):  
Yabin Shao ◽  
Chen Chen ◽  
Qing He ◽  
Wenzhi Wu ◽  
Chensha Li ◽  
...  
Keyword(s):  
Nonlinear Absorption ◽  
Transient Absorption ◽  
Laser Energy ◽  
Visible Region ◽  
Photon Absorption ◽  
Saturable Absorption ◽  
Reverse Saturable Absorption ◽  
Ultrafast Dynamics ◽  
Fast Decay ◽  
Broadband Absorption

The Ti3C2 nanosheet, as a new two-dimensional (2D) group, has been found to have attractive characteristics as material for electromagnetic shielding and energy storage. In this study, the nonlinear broadband absorption and ultrafast dynamics of the Ti3C2 nanosheet were investigated using nanosecond open-aperture Z-scan and transient absorption techniques. The mechanism of two-photon absorption (TPA) was revealed in the visible region (475–700 nm). At lower incident energies, nonlinear absorption could not happen. When the laser energy increased to 0.64 GW/cm2, electrons in the valence band could absorb two photons and jump to the conduction band, with TPA occurring, which meant that the sample exhibited reverse saturable absorption (RSA). In addition, when transient absorption was used to investigate the ultrafast carrier dynamics of the sample, it demonstrated that the relaxation contains a fast decay component and a slow one, which are obtained from electron–phonon and phonon–phonon interactions, respectively. Moreover, with the increasing pump fluence, the fast decay lifetime τ1 increased from 3.9 to 4.5 ps, and the slow one τ2 increased from 11.1 to 13.2 ps. These results show that the Ti3C2 nanosheet has potential applications in broadband optical limiters.

Optical Limiting Processes in Derivatized Fullerenes and Porphyrins/Phthalocyanines

1997 ◽  
Vol 488 ◽  
Author(s):  
R. Kohlman ◽  
V. Klimov ◽  
X. Shi ◽  
M. Grigorova ◽  
B. R. Mattes ◽  
...  
Keyword(s):  
Spectral Response ◽  
Sol Gel ◽  
Excited State Absorption ◽  
Damage Threshold ◽  
Optical Limiting ◽  
Spectral Studies ◽  
Saturable Absorption ◽  
Reverse Saturable Absorption ◽  
Dynamical Response ◽  
Gel Glasses

AbstractWe review our results from spectral studies of the ultrafast excited-state absorption in fullerenes and derivatized fullerenes. These results allow determination of both the spectral response of reverse saturable absorption (RSA) nonlinearities such as optical limiting (OL) in fullerenes, and the dynamical response for different morphologies. We have investigated the effects of thin film and various sol-gel glass environments on the nanosecond OL and femtosecond dynamics of derivatized fullerenes. These data provide evidence of decay pathways which compete with the intersystem crossing to a triplet from the initial singlet states. With appropriate processing, however, the OL response of derivatized-fullerene sol-gel glasses can be enhanced to approach that of the same molecule in solution, while significantly enhancing the optical damage threshold. The optical limiting of these derivatized fullerenes is compared with that of various porphyrin and phthalocyanine molecules.

Single State Absorption Spectra of Novel Nonlinear Optical Materials

1999 ◽  
Vol 597 ◽  
Author(s):  
Sean M. Kirkpatrick ◽  
Casey Clark ◽  
Richard L. Sutherland
Keyword(s):  
Excited State ◽  
Cross Section ◽  
Transient Absorption ◽  
Short Pulse ◽  
Measurement Techniques ◽  
Excited State Absorption ◽  
Leading Edge ◽  
Photon Absorption ◽  
Two Photon ◽  
Pulse Pump

AbstractDuring the absorption of a laser pulse of moderate length, the leading edge can experience excited state absorption out of the first singlet state. The measurement of this excited state absorption spectrum can only be accurately probed using short pulse pump-probe techniques. Specifically, we examine the excited state absorption of AF-380 in THF using ultrafast transient white light absorption spectroscopy (TWLA). This material has been the focus of several investigations due to it's purported large two-photon absorption cross-section, the discrepancies between long and short pulse measurements, and it's use in holographic twophoton induced photopolymerization. It is believed that a substantial excited state absorbance can account for the difference in two-photon cross section measurements. It is also possible that this excited state exhibits coherence for time scales that can affect further absorption of longer pump pulses. We examine the transient absorption of this species, as well as polarization and free carrier effects and discuss the possible implications with regards to measurement techniques.

Optical limiting properties of water-soluble phthalocyanine derivatives

2003 ◽  
Vol 07 (06) ◽  
pp. 447-451 ◽  
Author(s):  
Shuang Zhang ◽  
Zhou Yang ◽  
Hongwei Liu ◽  
Fu Xi ◽  
Zhi-xin Guo ◽  
...  
Keyword(s):  
Cross Section ◽  
Excited State Absorption ◽  
Optical Limiting ◽  
Water Soluble ◽  
Saturable Absorption ◽  
Reverse Saturable Absorption ◽  
Solubility In Water ◽  
Practical Applications ◽  
Good Solubility ◽  
532 Nm

The optical-limiting properties of several water-soluble phthalocyanine derivatives in aqueous solution were measured at 532 nm with 10 ns pulses. The excited state absorption cross-section σex of the derivatives were determined with the Z-scan technique. The results showed that the phthalocyanine derivatives are materials for reverse saturable absorption. It was noted that the optical limiting performance of the phthalocyanine derivatives in aqueous solutions can be controlled through the addition of alkalis. These phthalocyanine derivatives possess good solubility in water and optical limiting controllability, which give rise to their use for practical applications.

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