Two-Photon Excitation Enhanced High-Efficiency and Phase-Conjugate Stimulated Mie Scattering of Perovskite Nanocrystals Suspended in n-Hexane

Abstract

Two-photon excitation enhanced backward stimulated Mie scattering (SMS) is generated in a system of perovskite (CsPbBr x I 3-x ) nanocrystals (NCs) of ∼11 nm size suspended in nhexane, when pumped with ∼816 nm and ∼10 ns laser pulses. The major linear absorbance band of these PCs is in the 550−300 nm spectral range; thereby, at the pump wavelength (∼800 nm), a considerable two-photon excitation enhanced spatial redistribution of the PCs leads to the formation of an effective Bragg grating that ensures a lower pump threshold requirement and a higher energy transfer efficiency (η) from the pump pulse to the SMS output pulse. Under optimized experimental conditions, the measured efficiency in this system reaches a high value of η = 40%. In addition, the output backward SMS beam exhibits a superior optical phase-conjugation property, and the temporal behavior of SMS output has also verified the proposed theoretical model.

Enhanced Multiphoton Processes in Perovskite Metasurfaces

“…Second, we should select materials with extraordinary nonlinear responses. Over the past few years, many types of nonlinear materials have been developed. ,, Solution-processable lead halide perovskites (MAPbX 3 , X = Cl, Br, I, and their mixtures) have shown their clear advantages. ,− A high value of the refractive index ensures strong light confinement, whereas the exceptional nonlinear susceptibility is essential for nonlinear processes including third-harmonic generation and multiphoton stimulated emissions. ,, Here, by combining the intrinsic advantages of perovskites ,, with the concept of metamaterials, ,,,− we observe a giant enhancement of two-photon emission from MAPbBr 3 perovskite metasurfaces comparable with the one-photon processes.…”

“…The study of multiphoton absorption and luminescence from thin films has gained considerable attention during recent years owing to their importance in enriching the fundamental understanding of electronic, vibrational, and rotational states of various materials. In the past decades, several multiphoton processes have been observed and employed for applications such as optical storage, − stimulated scattering, , microscopy, − and nanofabrication. , Despite a rapid progress in this research direction, wider applications of multiphoton processes in optics are strongly limited because of their overall low efficiencies. As an example, two-photon absorption, being the third-order nonlinear process, requires an excitation power of 2–3 orders of magnitude higher than that required for linear absorption .…”

Chiral Lead Halide Perovskite Nanocrystals: Construction Strategies and Photophysical Properties

“…Nonlinear optics describes the nonlinear mechanisms of lightmatter interactions under strongly coherent light, which is the basis for many essential applications such as laser frequency conversion, [104] electro-optical modulation, [105] optical parametric oscillation, [106] and optical phase conjugation. [107] In such case, corresponding g abs at maximum CD peak (right). Reproduced with permission.…”

“…Nonlinear optics describes the nonlinear mechanisms of light–matter interactions under strongly coherent light, which is the basis for many essential applications such as laser frequency conversion, [ 104 ] electro‐optical modulation, [ 105 ] optical parametric oscillation, [ 106 ] and optical phase conjugation. [ 107 ] In such case, the nonlinear polarization P (t) of the medium is a power series of the electric field E (t), which is expressed by [ 108 ] $$$$\begin{equation}P{\mathrm{(t)\ = \ }}{\varepsilon _0}{\mathrm{(}}{\chi ^{{\mathrm{(1)}}}}E{\mathrm{(t)\ + \ }}{\chi ^{{\mathrm{(2)}}}}{E^{\mathrm{2}}}{\mathrm{(t)\ + \ }}{\chi ^{{\mathrm{(3)}}}}{E^{\mathrm{3}}}{\mathrm{(t)\ + \ }} \cdots {\mathrm{)}}\end{equation}$$$$where ε 0 is vacuum permittivity, χ (n) is the n‐th order of the electric susceptibility. When the superscript n is 1, χ (1) represents the linear optical term, while other high‐order terms are the category involved in nonlinear optics.…”

Research progress in optical activities and nonlinear optics of chiral perovskites

“…直到2017年, 本团队 [34] 和Ahn等人 [35] 相继 报道了手性钙钛矿纳米晶和薄膜的合成和光学活性, 手性钙钛矿这一研究领域才重新兴起并迅速引起了对 相关应用的探索, 如自旋LEDs [36] 、圆偏光探测器 [37] 、 铁电体材料 [38] 和非线性光学 [39] . 非线性光学描述了强光与物质作用的非线性机 制, 是电光调制 [40] 、激光频率转换 [41] 、光学参量振 荡 [42] 和光学位相共轭 [43] 等诸多应用的基础. 在非线性 光学中, 介质的极化P(t)是电场强度E(t)的幂级数, 具 体表示为…”