Enhanced third-order nonlinear optical properties of methyl orange dye-doped potassium penta borate octa hydrate (MOPPB) single crystals using CW diode laser for optical limiting applications

K Kamatchi,E Anuranjani,S Sriram,K Sangeetha,T C Sabari Girisun,M Durairaj

doi:10.1007/s10854-021-06067-2

Abstract

We report pure potassium penta borate octa hydrate (PPB) and methyl orange dye-doped potassium penta borate octa hydrate (MOPPB) for optical limiting applications. The crystals were grown by slow evaporation solution growth technique at ambient conditions. The single crystal X-ray diffraction (SXRD) evinces the orthorhombic class of the pristine and MOPPB crystals. Formation of PPB and incorporation of MO dye in PPB was confirmed through Fourier transform infrared (FTIR) study. Calculated hardness number and stiffness constant with Vicker’s Micro hardness study portrays the soft nature of the title crystals. The decrease in bandgap of MOPPB is due to the additional energy levels introduced between the valence band and conduction band which in turn increases the net polarizability of the crystal. Relative second harmonic generation (SHG) efficiency of pure PPB and MOPPB is 0.45 times and 0.40 times that of SHG output of KDP. Z-scan studies shows that both crystals show reverse saturable absorption (RSA) ascribed due to two-photon absorption (TPA) process. MOPPB [β = 1.68 × 10–5 m/W, n2 = 10.2 × 10–12 m2/W, χ(3) = 3.5 × 10–9 m2/V2] possess higher NLO coefficients than pure PPB [β = 0.98 × 10–5 m/W, n2 = 4.62 × 10–12 m2/W, χ(3) = 6.1 × 10–9 m2/V2] which assured the superiority of azo dye incorporation in PPB crystals. Pristine and MOPPB crystals depict the optical limiting (OL) behavior under continuous wave (CW) diode laser irradiation at 785 nm. Thus, the linear and nonlinear properties bestow the MOPPB single crystal as a versed material for OL devices used for the safeguard of optical components from laser damage.

Highlights

Nowadays, nonlinear optical (NLO) materials are overwhelmingly explored because of their dynamic and vibrant applications in telecommunications, optical switching, optical modulation, 3-D optical memory devices, optical limiters etc., [1]
It can be observed that the hardness number gradually increases with the applied load. Both pure Potassium Penta Borate octa hydrate (PPB) and methyl orange doped potassium penta borate (MOPPB) show the increase of hardness number with applied load thereby proving the Reverse Indentation Size Effect (RISE) [30]
PPB and MOPPB show the increase of hardness number with applied load (RISE) and soft nature of the material

Summary

Introduction

Nonlinear optical (NLO) materials are overwhelmingly explored because of their dynamic and vibrant applications in telecommunications, optical switching, optical modulation, 3-D optical memory devices, optical limiters etc., [1]. Azo dyes contain organic compounds which contain the colouring agent (N=N) possessing the functional group R-N=N-R’ where R’ and R are aryl groups When these dyes are doped into the host materials, they show improved nonlinear optical absorption phenomena such as Saturable Absorption (SA), Reverse Saturable Absorption (RSA), etc., [9,10]. This article reports the preparation and characterization of pure (PPB) and methyl orange doped potassium penta borate (MOPPB) for the optical limiting applications for the first time. Measure of Hardness value could say the measure of resistance to the permanent deformation or damage This mechanical stability of the grown bulk material depends on structure, lattice energy, binding energy, interatomic spacing and Debye temperature. Both the crystals belong to the soft nature and can be utilized for laser safety devices

Linear optical study

Nonlinear Optical Behavior

Conclusions

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