Two-photon absorption and spectroscopy

Bredikhin, V. I.; Galanin, M. D.; Genkin, V. N.

doi:10.1070/pu1973v016n03abeh005183

Cited by 43 publications

(12 citation statements)

References 6 publications

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“…This effect is possible in the absence of a central symmetry in the molecule and was observed earlier for certain organic phosphors [3]. The use of this type of phosphors as standards makes it possible to simplify the relative measurements of the TPA cross section.…”

Section: Introductionmentioning

confidence: 81%

Two-photon absorption cross section for Coumarins 102, 153 and 307

Melnikov

Serdobintsev

Vedyaykin³

et al. 2017

J. Phys.: Conf. Ser.

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Abstract. Two-photon absorption cross sections of Coumarins 102, 153, 307 solutions in methanol in the wavelength range of 730-870 nm were measured. The maximum cross section for two-photon absorption in this wavelength range were 267, 369, 287 GM for Coumarins 102, 153, 307, respectively. The absolute value of the cross sections was determined by comparison with a fluorescein (43 GM at a wavelength of 790 nm). The dependence of the two-photon absorption cross section on the excitation wavelength coincides with the shape of the single-photon absorption cross section. IntroductionMany novel research methods based on two-photon absorption (TPA), in particular multiphoton fluorescence microscopy, photodynamic therapy with TPA are currently being intensively developed. These methods use fluorescent probes, which are usually organic phosphors. Coumarins as a class of compounds are among the most versatile and widely used fluorescent probes. In biological preparations, coumarins show a high degree of sensitivity to the environment [1]. The photophysical properties of coumarins are well understood, however data on the TPA of coumarins are poor. The aim of this work was to study TPA of Coumarins 102, 153 and 307 in methanol solutions.It was found in paper [2] that the shape of the TPA cross section coincides with the one-photon absorption for the Coumarin 102 solution in methanol. This effect is possible in the absence of a central symmetry in the molecule and was observed earlier for certain organic phosphors [3]. The use of this type of phosphors as standards makes it possible to simplify the relative measurements of the TPA cross section. The Coumarins 102, 153 and 307 with a single-photon absorption maximum in the 375-435 nm region were chosen as the object of measurements, since their two-photon absorption corresponds to the widely used 730-870 nm range.

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Section: Introductionmentioning

confidence: 81%

Two-photon absorption cross section for Coumarins 102, 153 and 307

Melnikov

Serdobintsev

Vedyaykin³

et al. 2017

J. Phys.: Conf. Ser.

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“…In the NIR range of wavelengths, the most likely mechanisms include mid-gap absorption due to defects and two-photon absorption [40]. This latter process occurs when two photons are simultaneously absorbed, leading to an energy transition corresponding to the sum of their energies [41]. Typically, two-photon absorption only becomes the dominant absorption process at high optical intensities, and can be identified by a quadratic relationship between the optical absorption and incident photon rate [41].…”

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confidence: 99%

Near-infrared excitation of nitrogen-doped ultrananocrystalline diamond photoelectrodes in saline solution

Chambers

Ahnood

Falahatdoost

et al. 2020

Diamond and Related Materials

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Receipt date:PACS indexing codes: 87. 85.eg, 42.70.Km, 73.40.Mr, is a promising material for a variety of neural interfacing applications, due to its unique combination of high conductivity, bioinertness, and durability. One emerging application for N-UNCD is as a photoelectrode material for high-precision optical neural stimulation. This may be used for the treatment of neurological disorders and for implantable bionic devices such as cochlear ear implants and retinal prostheses. N-UNCD is a well-suited material for stimulation photoelectrodes, exhibiting a photocurrent response to light at visible wavelengths with a high charge injection density [A. Ahnood, A. N. Simonov, J. S. Laird, M. I. Maturana, K. Ganesan, A. Stacey, M. R. Ibbotson, L. Spiccia, and S. Prawer, Appl. Phys. Lett. 108, 104103 (2016)]. In this study, the photoresponse of N-UNCD to near-infrared (NIR) irradiation is measured. NIR light has greater optical penetration through tissue than visible wavelengths, opening the possibility to stimulate previously inaccessible target cells. It is found that N-UNCD exhibits a photoresponsivity which diminishes rapidly with increasing wavelength and is attributed to transitions between mid-gap states and the conduction band tail associated with the graphitic phase present at the grain boundaries. Oxygen surface termination on the diamond films provides further enhancement of the injected charge per photon, compared to as-grown or hydrogen terminated surfaces. Based on the measured injected charge density, we estimate that the generated photocurrent of oxygen terminated N-UNCD is sufficient to achieve extracellular stimulation of brain tissue within the safe optical exposure limit.The use of light-based techniques for neural stimulation is an area of growing interest, with potential applications in the treatment of neurological disorders and in implantable bionic devices [1][2][3][4]. In particular, optically-driven electrodes have the potential to offer wireless stimulation with much greater spatial resolution than conventional electrically-driven electrodes [2]. This approach relies on the transduction of light into electrical signals in order to stimulate neural tissue, caused by the separation of photo-excited charge carriers in a semiconducting electrode [2]. Materials such as photoconductive silicon [5][6][7][8], conductive polymers [9][10][11], and quantum dots [12][13][14] have been extensively studied for this purpose. However, these photoactive surfaces have often been found to exhibit limited biostability or produce cytotoxic reactions [15][16][17][18][19][20].

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“…Optical methods, especially those using resonances, are of higher sensitivity and preferable in the study of deep levels related to imperfections in seniiconductors. The results from a two-photon absorption technique are given in [3]. Recently, the optical third-order susceptibility ~(~1 is considered a s an important nonlinear parameter.…”

Section: Introductionmentioning

confidence: 99%

Third-order optical polarizability of ZnS at low temperature

Mileva¹,

Pavlov

1985

phys. stat. sol. (a)

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Third‐order optical polarizability near deep centers in ZnS is experimentally investigated for the case of ultrashort light pulses at low temperature of the sample. Dispersion of the optical nonlinearity is characterized with resonant lines located at 16660, 17110, and 17540 cm−1. Higher resolution of the polarization four‐photon spectroscopy is demonstrated, which delivers additional information about the energy structure. Use of the mode‐locked laser pulses allows to extend the range of the pump intensity applied to the single crystal. Comparing of the experimental results with a conventional method is performed.

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Two-photon absorption and spectroscopy

Cited by 43 publications

References 6 publications

Two-photon absorption cross section for Coumarins 102, 153 and 307

Two-photon absorption cross section for Coumarins 102, 153 and 307

Near-infrared excitation of nitrogen-doped ultrananocrystalline diamond photoelectrodes in saline solution

Third-order optical polarizability of ZnS at low temperature

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