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T. Pottenger

Bio: T. Pottenger is an academic researcher from Wright-Patterson Air Force Base. The author has contributed to research in topics: Two-photon absorption & Hyperpolarizability. The author has an hindex of 3, co-authored 4 publications receiving 321 citations.

Papers
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Journal ArticleDOI
TL;DR: A five-level model of C60 yields excellent agreement with both pulse-width data sets for incident fluences as high as approximately 1 J/cm2 and additional phenomena observed at higher fluences indicate that other mechanisms may be active and contribute to optical limiting in this regime.
Abstract: Nonlinear absorption at 532 nm in a C60–toluene solution by using 8-ns and 30-ps laser pulses is reported. The transmittance for both pulse widths is fluence dependent. A five-level model of C60 is described that yields excellent agreement with both pulse-width data sets for incident fluences as high as approximately 1 J/cm2. Additional phenomena observed at higher fluences indicate that other mechanisms may be active and contribute to optical limiting in this regime. The application of C60 as an optical limiter material is discussed.

284 citations

Journal ArticleDOI
TL;DR: Double-peaked phase-conjugate pulses in the degenerate four-wave mixing of nanosecond laser pulses in solutions of diphenyl polyenes are observed, supported by the results of time delay and polarization experiments as well as evidence of a second spatial harmonic grating.
Abstract: We have observed double-peaked phase-conjugate pulses in the degenerate four-wave mixing of nanosecond laser pulses in solutions of diphenyl polyenes. We attribute this to the superposition of fast and slow gratings, where the slow grating is due to two-photon absorption. This is supported by the results of time delay and polarization experiments as well as evidence of a second spatial harmonic grating.

20 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used degenerate four-wave mixing (DFWM) of nanosecond laser pulses to measure the second hyperpolarizability of solute molecules.
Abstract: We have investigated two‐photon absorption (TPA) in diphenylbutadiene at 532 nm using degenerate four‐wave mixing (DFWM) of nanosecond laser pulses. We present a theory which describes the development of double‐peaked phase conjugate pulses produced in DFWM due to TPA‐induced gratings superimposed on the usual electronic third‐order processes. Our analysis suggests a novel technique for measuring both the real and imaginary parts of the third‐order susceptibility of a molecular solution, hence leading to a determination of the TPA cross section σ2 and second hyperpolarizability γ of the solute molecules. Applying this experimental technique to diphenylbutadiene in chloroform, we obtain σ2=(40±8)×10−50 cm−4 s/photon–molecule and ‖γ‖=(420±80)×10−36 esu for this diphenyl polyene. We show that these values are in agreement with related measurements in diphenylbutadiene, and that they are consistent with a two‐photon resonance near 39 500 cm−1. The DFWM measurement technique we describe is very sensitive and should be applicable for measuring the two‐photon spectra of a variety of molecules.

18 citations

Journal ArticleDOI
TL;DR: In this article, the authors used degenerate four-wave mixing (DFWM) of nanosecond laser pulses to measure the second hyperpolarizability of solute molecules.
Abstract: We have investigated two‐photon absorption (TPA) in diphenylbutadiene at 532 nm using degenerate four‐wave mixing (DFWM) of nanosecond laser pulses. We present a theory which describes the development of double‐peaked phase conjugate pulses produced in DFWM due to TPA‐induced gratings superimposed on the usual electronic third‐order processes. Our analysis suggests a novel technique for measuring both the real and imaginary parts of the third‐order susceptibility of a molecular solution, hence leading to a determination of the TPA cross section σ2 and second hyperpolarizability γ of the solute molecules. Applying this experimental technique to diphenylbutadiene in chloroform, we obtain σ2=(40±8)×10−50 cm−4 s/photon–molecule and ‖γ‖=(420±80)×10−36 esu for this diphenyl polyene. We show that these values are in agreement with related measurements in diphenylbutadiene, and that they are consistent with a two‐photon resonance near 39 500 cm−1. The DFWM measurement technique we describe is very sensitive and should be applicable for measuring the two‐photon spectra of a variety of molecules.

1 citations


Cited by
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Journal ArticleDOI
TL;DR: Nonlinear Optical Characterizations of Multiphoton Active Materials 1282 5.2.1.
Abstract: 4. Survey of Novel Multiphoton Active Materials 1257 4.1. Multiphoton Absorbing Systems 1257 4.2. Organic Molecules 1257 4.3. Organic Liquids and Liquid Crystals 1259 4.4. Conjugated Polymers 1259 4.4.1. Polydiacetylenes 1261 4.4.2. Polyphenylenevinylenes (PPVs) 1261 4.4.3. Polythiophenes 1263 4.4.4. Other Conjugated Polymers 1265 4.4.5. Dendrimers 1265 4.4.6. Hyperbranched Polymers 1267 4.5. Fullerenes 1267 4.6. Coordination and Organometallic Compounds 1271 4.6.1. Metal Dithiolenes 1271 4.6.2. Pyridine-Based Multidentate Ligands 1272 4.6.3. Other Transition-Metal Complexes 1273 4.6.4. Lanthanide Complexes 1275 4.6.5. Ferrocene Derivatives 1275 4.6.6. Alkynylruthenium Complexes 1279 4.6.7. Platinum Acetylides 1279 4.7. Porphyrins and Metallophophyrins 1279 4.8. Nanoparticles 1281 4.9. Biomolecules and Derivatives 1282 5. Nonlinear Optical Characterizations of Multiphoton Active Materials 1282

1,864 citations

Journal ArticleDOI
TL;DR: Representative results concerning the solubility, dispersion, defunctionalization, and optical properties of the functionalized carbon nanotubes are presented.
Abstract: Carbon nanotubes can be functionalized via amidation and esterification of the nanotube-bound carboxylic acids. The solubility of these functionalized carbon nanotubes makes it possible to characterize and study the properties of carbon nanotubes using solution-based techniques. Representative results concerning the solubility, dispersion, defunctionalization, and optical properties of the functionalized carbon nanotubes are presented. Several examples for the use of functionalized carbon nanotubes in the fabrication of polymeric carbon nanocomposites, the probing of nanotube-molecule interactions, and the conjugation with biological species are highlighted and discussed.

1,542 citations

Journal ArticleDOI
TL;DR: In this paper, the formation of switchable holographic gratings from polymer-dispersed liquid crystals (H-PDLCs) allows for the development of turnable transmissive and reflective diffractive optics, created by coherent interference of laser radiation within a syrup containing photoreactive monomer, initiator, and liquid crystal.
Abstract: ▪ Abstract The formation of switchable holographic gratings from polymer-dispersed liquid crystals (H-PDLCs) allows for the development of switchable transmissive and reflective diffractive optics. These structures are created by the coherent interference of laser radiation within a syrup containing photoreactive monomer, initiator, and liquid crystal. Local differences in photopolymerization rates induce phase separation of discrete LC domains to occur periodically commensurate with the period of the interference pattern. These spatially periodic gratings of nano-scale sized LC domains can be formed on grating length scales ranging from 100 nm to microns depending on the optics of fabrication. True Bragg gratings are formed with spacings typically less than 1 μm. Owing to the refractive profile generated by this periodic two-phase structure, diffraction of light occurs. Electrical switching of the average director orientation within the LC domains results in a modulation of diffracted radiation. This tec...

584 citations

Journal ArticleDOI
TL;DR: In this paper, the reverse saturable absorbers (RSA) and chromophores with large two-photon cross-sections are combined to design bimechanistic optical power limiters.
Abstract: During the past five years there has been considerable progress in the design of organic materials for optical power limiting. Among the more promising of the new material approaches are new reverse saturable absorbers (RSA) which derive their limiting capability on the photogeneration of highly absorbing charge states. Equally intriguing are the new approaches to designing chromophores with large two-photon cross-sections which give access to highly absorbing transient excited states. It now seems possible to combine these two new optical limiting paradigms in single structures which may therefore be considered as bimechanistic optical power limiters.

495 citations

Journal ArticleDOI
TL;DR: Results show that covalently functionalizing graphene with the reverse saturable absorption chromospheres porphyrin and fullerene can enhance the nonlinear optical performance in the nanosecond regime.
Abstract: The nonlinear optical properties of two novel graphene nanohybrid materials covalently functionalized with porphyrin and fullerene were investigated by using the Z-scan technique at 532 nm in the nanosecond and picosecond time scale. Results show that covalently functionalizing graphene with the reverse saturable absorption chromospheres porphyrin and fullerene can enhance the nonlinear optical performance in the nanosecond regime. The covalently linked graphene nanohybrids offer performance superior to that of the individual graphene, porphyrin, and fullerene by combination of a nonlinear mechanism and the photoinduced electron or energy transfer between porphyrin or fullerene moiety and graphene.

435 citations