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.

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.

Reverse saturable Absorption in Organically Doped Xerogels

1997 ◽  
Vol 479 ◽  
Author(s):  
M. Brunel ◽  
F. Chaput ◽  
S. A. Vinogradov ◽  
B. Campagne ◽  
M. Canva ◽  
...  
Keyword(s):  
Solid State ◽  
Sol Gel ◽  
Visible Spectrum ◽  
Laser Pulses ◽  
Saturable Absorption ◽  
Nanosecond Laser ◽  
Reverse Saturable Absorption ◽  
Saturable Absorbers ◽  
Sol Gel Process ◽  
Nanosecond Laser Pulses

AbstractPd and Zn - tetraphenyltetrabenzoporphyrins (PdTPTBP and ZnTPTBP), hexacyanin 3 (HITCI), and substituted phthalocyanines were incorporated in solid-state matrices (xerogels) using a sol-gel process. Nonlinear reverse saturable absorption was observed with those materials when they were illuminated with nanosecond laser pulses at 532 nm, or other wavelengths in the visible spectrum (between 450 nm and 630 nm). PdTPTBP doped xerogels exhibit a nonlinear activation threshold of about 10 mJ/cm , which is much lower than the value of 80 mJ/cm2 obtained under similar conditions with classical Al phthalocyanine chloride, or HITCI molecules. Solid state “red active” reverse saturable absorbers can be obtained with substituted phthalocyanines doped xerogels. The different experimental results are discussed using classical 4- energy level diagrams.

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.

scholarly journals Ultrafast nonequilibrium dynamic process of separate electron and hole during exciton formation in few-layer tungsten disulfide

2021 ◽  
Author(s):  
Junjie Chen ◽  
Sen Guo ◽  
Dabin Lin ◽  
Zhaogang Nie ◽  
Chung-Che Huang ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Dynamic Process ◽  
Formation Process ◽  
Transient Absorption ◽  
Tungsten Disulfide ◽  
Transient Absorption Spectroscopy ◽  
Femtosecond Transient Absorption ◽  
Nonequilibrium Dynamic ◽  
Femtosecond Transient Absorption Spectroscopy ◽  
Separate Electron

Femtosecond transient absorption spectroscopy has been employed to unravel separate initial nonequilibrium dynamic process of photo-injected electrons and holes during the formation process of the lowest excitons at the K-valley...

scholarly journals SnSe Nanosheets: From Facile Synthesis to Applications in Broadband Photodetections

Nanomaterials ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 49
Author(s):  
Xiangyang Li ◽  
Zongpeng Song ◽  
Huancheng Zhao ◽  
Wenfei Zhang ◽  
Zhenhua Sun ◽  
...  
Keyword(s):  
Transient Absorption ◽  
Ultrafast Optics ◽  
Light Response ◽  
Transient Absorption Spectroscopy ◽  
Monolayer Graphene ◽  
Proof Of Concept ◽  
Facile Synthesis ◽  
Femtosecond Transient Absorption ◽  
Potential Applications ◽  
Promising Area

In recent years, using two-dimensional (2D) materials to realize broadband photodetection has become a promising area in optoelectronic devices. Here, we successfully synthesized SnSe nanosheets (NSs) by a facile tip ultra-sonication method in water-ethanol solvent which was eco-friendly. The carrier dynamics of SnSe NSs was systematically investigated via a femtosecond transient absorption spectroscopy in the visible wavelength regime and three decay components were clarified with delay time of τ1 = 0.77 ps, τ2 = 8.3 ps, and τ3 = 316.5 ps, respectively, indicating their potential applications in ultrafast optics and optoelectronics. As a proof-of-concept, the photodetectors, which integrated SnSe NSs with monolayer graphene, show high photoresponsivities and excellent response speeds for different incident lasers. The maximum photo-responsivities for 405, 532, and 785 nm were 1.75 × 104 A/W, 4.63 × 103 A/W, and 1.52 × 103 A/W, respectively. The photoresponse times were ~22.6 ms, 11.6 ms, and 9.7 ms. This behavior was due to the broadband light response of SnSe NSs and fast transportation of photocarriers between the monolayer graphene and SnSe NSs.

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