Anisotropic Nonlinear Optical and Optical Limiting Studies of an Ethylenediamminium Picrate Crystal with Femtosecond Excitation

Abstract

Femtosecond laser excitation (800 nm, ∼150 fs, 80 MHz) induced anisotropic nonlinear optical behaviour and optical limiting action of ethylenediamminium picrate (EDAPA) crystal along two prominent orientations (2 0 0) and (1 1 1) was studied using the Z‐scan technique. EDAPA exhibited reverse saturable type nonlinear absorption ascribed to two‐photon absorption (2PA) process and self‐defocusing based on nonlinear refraction. Intensity dependent nonlinear absorption studies portray the 2PA coefficient is independent of the peak intensity of excitation. Frontier molecular orbitals studies revealed the non‐availability of real states at laser excitation (1.55 eV) and the measured energy gap of 3.18 eV avails the energy states for simultaneous absorption of two photons involving virtual states leading to the occurrence of genuine 2PA. In addition, using molecular electrostatic potential (MEP) analyses polarizability (5.30×10−24 esu) and dipole moment (7.317 Debye) were calculated using the density functional theory. A variation in the NLO coefficients with respect to orientation of excitation arises due to the anisotropy of the crystal. EDAPA crystal along (1 1 1) orientation has high laser damage threshold (9.1 GW/cm2) and low optical limiting threshold (24.36 μJ/cm2) and thus the wide dynamic range make it a preferred candidate towards laser safety devices for high repetition rate ultrashort laser pulse excitation.

Rapid preparation of N,B-codoped carbon quantum dot based films with strong two-photon absorption and optical limiting effect

“…The E g of the N,B-CQDs is 3.99 eV, which satisfies 2.33 eV < 3.99 eV < 2 × 2.33 eV; thus N,B-CQDs show two-photon absorption. 29…”

“…The E g of the N,B-CQDs is 3.99 eV, which satisfies 2.33 eV o 3.99 eV o 2 Â 2.33 eV; thus N,B-CQDs show two-photon absorption. 29 When Z = 0 mm, the normalized transmittance of the N,B-CQD solution with T lin = 80% is 88.7%, 87.4%, 86.5%, and 84.8% at incident laser intensities of 1.39 Â 10 13 , 6.01 Â 10 13 The closed-aperture Z-scan curves of the N,B-CQD solutions of three concentrations firstly show the shape of a peak and then a valley when the incident laser energy increased gradually (i.e. a nonlinear refractive index n o 0), suggesting these solutions show self-defocusing behavior under laser irradiation.…”

Enhanced Optical Nonlinearity in Bi3+-Doped CePO4 Nanostructures for Optical Limiting Applications

“…Among them, laser technology has recently drawn more importance with its widespread practical applications in laser surgery, optical imaging, industrial processing communication, etc. Due to this, there has been an alarming increase in laser usage, resulting in numerous laser accidents, which necessitates the development of proper laser safety devices capable of protecting photosensitive optical components from laser-induced damage . As a result of the high demand, optical limiting (OL) technology has progressed significantly.…”

“…Due to this, there has been an alarming increase in laser usage, resulting in numerous laser accidents, which necessitates the development of proper laser safety devices capable of protecting photosensitive optical components from laser-induced damage. 5 As a result of the high demand, optical limiting (OL) technology has progressed significantly. Optical limiters are materials that are relatively transparent to low-intensity light.…”