scholarly journals Improved two-photon imaging of GPCR-based optogenetic neurotransmitter sensors using orthogonally polarized excitation

2021 ◽  
Author(s):  
Mauro Pulin ◽  
Kilian E. Stockhausen ◽  
Olivia Andrea Masseck ◽  
Martin Kubitschke ◽  
Bjoern Busse ◽  
...  
Keyword(s):  
Fluorescent Proteins ◽  
Second Harmonic ◽  
Polarized Light ◽  
Optical Measurements ◽  
Orthogonal Polarization ◽  
Polarization Sensitivity ◽  
Tubular Structures ◽  
Excitation Beam ◽  
Two Photon ◽  
Orientation Bias

Fluorescent proteins such as GFP are best excited by light that is polarized parallel to the dipole axis of the fluorophore. In most cases, fluorescent proteins are randomly oriented, resulting in unbiased images even when polarized light is used for excitation, e.g. in two-photon microcopy. Here we reveal a surprisingly strong polarization sensitivity in a class of GPCR-based neurotransmitter sensors where the fluorophore is anchored on both ends. In tubular structures such as dendrites, this effect led to a complete loss of membrane signal in dendrites running parallel to the polarization direction of the excitation beam. Our data reveal a major problem for two-photon measurements of neurotransmitter concentration that has not been recognized by the neuroscience community. To remedy the sensitivity to dendritic orientation, we designed an optical device that generates interleaved pulse trains of orthogonal polarization, removing the orientation bias from images. The passive device, which we inserted in the beam path of an existing two-photon microscope, also removed the strong direction bias in second harmonic generation (SHG) images. We conclude that for optical measurements of transmitter concentration with GPCR-based sensors, orthogonally polarized excitation is essential.

scholarly journals Nonlinear optical spectroscopy and two-photon excited fluorescence spectroscopy reveal the excited states of fluorophores embedded in a beetle’s elytra

2018 ◽  
Vol 9 (1) ◽  
pp. 20180052 ◽  
Author(s):  
Sébastien R. Mouchet ◽  
Charlotte Verstraete ◽  
Dimitrije Mara ◽  
Stijn Van Cleuvenbergen ◽  
Ewan D. Finlayson ◽  
...  
Keyword(s):  
Excited States ◽  
Nonlinear Optical ◽  
Polarization State ◽  
Polarized Light ◽  
Fluorescence Emission ◽  
Biological Tissues ◽  
Optical Measurements ◽  
Fluorescence Signal ◽  
Photonic Structure ◽  
Two Photon

Upon illumination by ultraviolet light, many animal species emit light through fluorescence processes arising from fluorophores embedded within their biological tissues. Fluorescence studies in living organisms are however relatively scarce and so far limited to the linear regime. Multiphoton excitation fluorescence analyses as well as nonlinear optical techniques offer unique possibilities to investigate the effects of the local environment on the excited states of fluorophores. Herein, these techniques are applied for the first time to study of the naturally controlled fluorescence in insects. The case of the male Hoplia coerulea beetle is investigated because the scales covering the beetle’s elytra are known to possess an internal photonic structure with embedded fluorophores, which controls both the beetle’s coloration and the fluorescence emission. An intense two-photon excitation fluorescence signal is observed, the intensity of which changes upon contact with water. A third-harmonic generation signal is also detected, the intensity of which depends on the light polarization state. The analysis of these nonlinear optical and fluorescent responses unveils the multi-excited states character of the fluorophore molecules embedded in the beetle’s elytra. The role of form anisotropy in the photonic structure, which causes additional tailoring of the beetle’s optical responses, is demonstrated by circularly polarized light and nonlinear optical measurements.

scholarly journals Enhanced two-photon photoluminescence assisted by multi-resonant characteristics of a gold nanocylinder

Nanophotonics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 4009-4019
Author(s):  
Artur Movsesyan ◽  
Gwénaëlle Lamri ◽  
Sergei Kostcheev ◽  
Anke Horneber ◽  
Annika Bräuer ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Enhancement Factor ◽  
Second Harmonic ◽  
Plasmon Mode ◽  
Excitation Wavelength ◽  
Resonant System ◽  
Two Photon ◽  
Plasmon Resonances ◽  
Resonant Systems ◽  
Photoluminescence Enhancement

AbstractMulti-resonant plasmonic simple geometries like nanocylinders and nanorods are highly interesting for two-photon photoluminescence and second harmonic generation applications, due to their easy fabrication and reproducibility in comparison with complex multi-resonant systems like dimers or nanoclusters. We demonstrate experimentally that by using a simple gold nanocylinder we can achieve a double resonantly enhanced two-photon photoluminescence of quantum dots, by matching the excitation wavelength of the quantum dots with a dipolar plasmon mode, while the emission is coupled with a radiative quadrupolar mode. We establish a method to separate experimentally the enhancement factor at the excitation and at the emission wavelengths for this double resonant system. The sensitivity of the spectral positions of the dipolar and quadrupolar plasmon resonances to the ellipticity of the nanocylinders and its impact on the two-photon photoluminescence enhancement are discussed.

scholarly journals Nonlinear optical microscopies (NOMs) and plasmon-enhanced NOMs for biology and 2D materials

Nanophotonics ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1341-1358
Author(s):  
Jialin Ma ◽  
Mengtao Sun
Keyword(s):  
Raman Scattering ◽  
Nonlinear Optical ◽  
Stimulated Raman Scattering ◽  
Second Harmonic ◽  
2D Materials ◽  
Research Progress ◽  
Two Photon ◽  
Two Dimensional Materials ◽  
Anti Stokes ◽  
Physical Principles

AbstractIn this review, we focus on the summary of nonlinear optical microscopies (NOMs), which are stimulated Raman scattering (SRS), coherent anti-Stokes Raman scattering (CARS), second harmonic generation (SHG), and two-photon excited fluorescence (TPEF). The introduction is divided into two parts: the principle of SRS, CARS, TPEF, and SHG and their application to biology and two-dimensional materials. We also introduce the connections and differences between them. We also discuss the principle of plasmon-enhanced NOM and its application in the above two aspects. This paper not only summarizes the research progress in the frontier but also deepens the readers’ understanding of the physical principles of these NOMs.

OPTICAL NONLINEARITY VIA PHONONS AS AN INTERMEDIARY

2001 ◽  
Vol 10 (01) ◽  
pp. 65-77 ◽  
Author(s):  
OU FA ◽  
HE MINGGAO ◽  
WU FUGEN
Keyword(s):  
Second Harmonic ◽  
Optical Nonlinearity ◽  
Photon Absorption ◽  
Saturation Phenomenon ◽  
Sum Frequency ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Threshold Phenomenon ◽  
Anti Stokes ◽  
The Given

A new model to describe the origin of optical nonlinearity is presented. In this model, the interaction between light and medium is reduced to the coupling of photons with phonons, which occurs in the crystal lattice vibrating anharmonically. Then the optical nonlinearity originates from the nonlinear photon–phonon coupling or the interaction among phonons themselves. In this paper, more attention is drawn to the latter. By the given model, (1) degenerate and (2) nondegenerate parametric oscillations, (3) Stokes and (4) anti-Stokes Raman scattering, (5) sum-frequency and (6) second harmonic generation and (7) two-photon absorption are dealt with systematically and quantum-mechanically. The results of theoretical analysis show that the effects (1)–(4) are associated with threshold phenomenon, whereas the effects (5)–(7) with the saturation phenomenon.

scholarly journals Ultraviolet polarization vision in fishes: possible mechanisms for coding e–vector

2000 ◽  
Vol 355 (1401) ◽  
pp. 1187-1190 ◽  
Author(s):  
Craig W. Hawryshyn
Keyword(s):  
Polarized Light ◽  
Spatial Arrangement ◽  
Short Review ◽  
Research Problem ◽  
Polarization Sensitivity ◽  
Polarization Vision ◽  
Selective Reflection ◽  
Mosaic Pattern ◽  
Cone Mosaic ◽  
Biophysical Mechanism

Polarization vision in vertebrates has been marked with significant controversy over recent decades. In the last decade, however, models from two laboratories have indicated that the spatial arrangement of photoreceptors provides the basis for polarization sensitivity.Work in my laboratory, in collaboration with I. Novales Flamarique and F. I. Harosi, has shown that polarization sensitivity depends on a well–defined square cone mosaic pattern and that the biophysical properties of the square cone mosaic probably account for polarization vision in the ultraviolet spectrum. The biophysical mechanism appears to be based on the selective reflection of axial–polarized light by the partitioning membrane, formed along the contact zone between the members of the double cones, onto neighbouring ultraviolet–sensitive cones. In this short review, I discuss the historical development of this research problem.

Interactions of picosecond laser pulses with organic molecules I. Two-photon fluorescence quenching and singlet states excitation in Rhodamine dyes

1972 ◽  
Vol 328 (1572) ◽  
pp. 97-121 ◽  
Keyword(s):  
Rhodamine 6G ◽  
Second Harmonic ◽  
Random Phase ◽  
Stimulated Emission ◽  
Photon Absorption ◽  
Picosecond Pulses ◽  
Two Photon ◽  
Singlet States ◽  
Two Photon Fluorescence ◽  
Photon Fluorescence

Intensity dependent quenching and reversal of the two-photon fluorescence patterns in Rhodamine 6G and DPA, of picosecond pulses from a mode-locked ruby laser have been investigated by measurements of the two-photon fluorescence efficiencies of these dyes. While for Rhodamine 6G there was a marked departure from the square law dependence at high laser intensities, the experimental curve for DPA showed no evidence of quenching. When excited by a mode-locked neodymium: glass laser Rhodamine 6G fluorescence was not quenched at fluxes as high as 5 x 10 30 photons cm -2 s -1 but in Rhodamine B quenching appeared at a laser flux of 3 x 10 27 photons cm -2 s -1 . These quenching results and measurements of the absorption of pulses by Rhodamine 6G, previously excited by second harmonic pulses, are explained by the effects of single photon absorption and stimulated emission from the S 1 and S 2 excited singlet states. A square pulse approximation has been employed to solve the general rate equations and the fitting of the calculated curves to the experimental results gave values for the stimulated emission and absorption cross-sections of the S 1 and S 2 states of Rhodamine 6G and for the relaxation time (~ 2 ps) between the vibrational manifolds of these excited states. Taking into account random phase and amplitude fluctuations of the picosecond pulses, time and space averaged two-photon fluorescence profiles, using these values of the dye parameters, showed quenching and reversal of the patterns for the laser pulse intensities at which these effects were experimentally observed. The possibilities of frequency tunable pulses, of transform-limited durations, from mode-locked dye lasers employed with an electro-optical streak camera of time-resolution equal to that of the pulse durations (~ 2 ps) for time-resolved excited state molecular spectroscopy are briefly considered.

Extracting diagnostic stromal organization features based on intrinsic two-photon excited fluorescence and second-harmonic generation signals

2009 ◽  
Vol 14 (2) ◽  
pp. 020503 ◽  
Author(s):  
Shuangmu Zhuo ◽  
Jianxin Chen ◽  
Shusen Xie ◽  
Zhibin Hong ◽  
Xingshan Jiang
Keyword(s):  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Second Harmonic ◽  
Two Photon
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