Analysis of electro-optically adjustable cascaded second-order nonlinearity in tapered BBO crystal: a compression scheme for ultra-short pulse

Abstract

In this analytical approach, electro-optically tunable second-order cascaded nonlinearity was targeted to investigate the potential of ultrashort pulse compression in a tapering nonlinear medium. The proposed framework is ideally suited to generating high-intensity pulses with small pulse widths by exploiting second-harmonic generation and the electro-optic effect in a bulk beta-barium borate with exceptional optical advantages. Considering both linear and nonlinear absorption losses, the necessary and sufficient conditions for the compression of ultrashort pulses were developed using the generalized nonlinear Schrödinger equation. In agreement with simulations, an attempt is made to compress an optical pulse from 120 to 39 fs using an external voltage of ∓5.69 KV, which leads to a phase mismatch ðΔk Þ ¼ AE124.8 m −1 , a phase shift ðΔϕ NL Þ ¼ AE1.26π, and an effective cascaded refractive index ðn cascade 2 Þ ¼ AE3.371 × 10 −20 m 2 ∕W. The results suggest that the technology developed in this study will open the door to a plethora of applications, including fields as diverse as laser surgery, range finding through LIDAR, and many more.