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Updated: Dec 14, 2025
A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference
Published on: September 5, 2019
Disentangling Second Harmonic Generation from Multiphoton Photoluminescence in Halide Perovskites using
Darien J Morrow1, Matthew P Hautzinger1, David P Lafayette1
1Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States.
Abstract:
Layered two-dimensional Ruddlesden-Popper (RP) halide perovskites are an intriguing class of semiconductors being explored for their linear and nonlinear optical and ferroelectric properties. Second harmonic generation (SHG) is commonly used to screen for noncentrosymmetric and ferroelectric materials. However, SHG measurements of perovskites can be obscured by their intense multiphoton photoluminescence (mPL). Here, we apply multidimensional harmonic generation as a method to eliminate the complications from mPL. By scanning and correlating both excitation and emission frequencies, we unambiguously assess whether a material supports SHG by examining if an emission feature scales as twice the excitation frequency. Measurements of a series of n = 2, 3 RP perovskites reveal that, contrary to previous belief, n-butylammonium (BA) RP perovskites are not SHG-active and thus centrosymmetric, but RP perovskites with phenylethylammonium (PEA) and 2-thiophenemethylammonium (TPMA) spacer cations display SHG. This work establishes multidimensional harmonic generation as a definitive method to measure SHG in halide perovskites.
