Frequency-upconverted organic crystal

Abstract

The fluorescent characteristics of Troger's base have been investigated experimentally. A one-photon-induced fluorescent spectrum was observed, and the peak wavelength was at 337 nm with a full width at half-maximum of ~85nm . The violet radiation of the Troger's base crystal could result from the pi(*) -pi transition of the benzenoid pi bond. Two-photon-pumped frequency-upconverted fluorescence was obtained, which is a wideband emission with the main peak wavelength at 337 nm and a subordinate peak. Donor groups and acceptor groups of electrons in the aromatic rings strengthen the two-photon-pumped frequency-upconverted fluorescence.

Two-Photon Excited Fluorescence and Second-Harmonic Generation of the DAST Organic Nanocrystals

“…Aside from the strong SHG scattering, surprisingly, the fluorescence emission was red-shifted and changed from broad emission to narrow emission when the excitation wavelength was increased gradually from 810 to 930 nm. The red-shift of the emission peak could result from different energy levels in the relaxation process, 4 which was further verified by the emission spectra from the solid state DAST ONCs as shown in Figure 4b. The fluorescence emission from solid DAST nanocrystals which was prepared with CSiO-G3/DAST = 8.5:1 is shown in spectrum a, excited by 475 nm, and the emission spectra of bulk crystal are shown in spectrum b, excited by 474 nm.…”

“…1À3 Until now, the investigations on the optical nonlinearities including two-photon excited fluorescence (TPEF) property and polarization response in the second-harmonic generation (SHG) have been done in solutions, dye-doped films, and bulk crystals. 4,5 It is well-known that organic nanocrystals (ONCs) show not only size-dependent multicolor emission but also aggregationenhanced fluorescence. 6À8 However, further investigation of the NLO properties of ONCs has been hindered.…”

Two-Photon Absorption Spectrum of a Single Crystal Cyanine-like Dye

“…Two-photon absorption (2PA), an instantaneous χ (3) optical nonlinear process, has potential applications in microfabrication, , optical data storage, optical limiting, microscopic imaging, and upconverted emission for laser applications. − The search for large 2PA materials spans from bulk solid-state materials (e.g., semiconductors), to engineered nanostructured materials (e.g., semiconductor quantum dots), and to organic molecules. , Organic molecules possess the advantage of greater degrees of freedom in custom material design and fabrication. With the capability to enhance nonlinear optical properties by directional modification of their molecular structures, cyanine-like dyes exhibit a linear extended π-conjugated system with π-electrons delocalized along the molecular backbone.…”

Temporal dynamics of two-photon-pumped amplified spontaneous emission in slab organic crystals

“…The recent demonstration of two-photon-pumped (TPP) stimulated emission in the organic crystals has stirred widespread attention for its potential compact solidstate upconversion laser application [8,[11][12][13][14]. Different with one-photon absorption, two-photon absorption is a nonlinear process, where two photons are absorbed simultaneously through a virtual state.…”