近年來，準二維鈣鈦礦因具備較高的激子束縛能、強振盪子強度及良好的環境穩定性，使其在光與物質耦合及激子極化子研究中廣受關注。然而，傳統溶液製程容易產生多相共存與厚度不均勻的現象，進而限制微共振腔品質及激子–光子耦合。
本研究採用空間受限成長法成功製備 BA2MAn-1PbnI3n+1 (n = 1-3) 純相準二維鈣鈦礦微晶板。藉由受限空間中的緩慢結晶，進而有效抑制多相的形成，成功獲得大面積、高結晶性且厚度均勻的微晶薄片，其天然平行的上下表面可形成法布里–珀羅微共振腔。其中，BA2MA2Pb3I10 (n = 3) 展現最佳的結晶品質與光學特性，並具有穩定的激子特性及清晰的法布里-珀羅共振模態。
為探討其光與物質的交互作用，本研究利用羅倫茲振盪子模型及角度解析反射光譜分析激子-光子耦合特性。結果顯示，能量-波向量色散關係呈現明顯的反交叉現象，證實 BA2MA2Pb3I10 微共振腔中已形成激子極化子。此外，在77 K脈衝雷射激發下成功觀察到放大自發放射，其閾值約為 0.16 mJ/cm²，顯示材料具有優異的光增益能力。
綜合上述結果，本研究證實空間受限成長法可有效製備高品質純相準二維鈣鈦礦微晶板，並成功展示其激子極化子行為及優異的光增益特性，為未來低閾值極化子雷射、極化子光子元件及新型相干光源之發展提供重要基礎。

Quasi-two-dimensional (quasi-2D) perovskites (PVSKs) have attracted considerable attention for studies of light–matter coupling and exciton–polaritons because of their strong exciton binding energies, high oscillator strengths, and excellent environmental stability. However, conventional solution-based methods often produce mixed-phase crystals and thickness nonuniformity, limiting microcavity quality and exciton–photon coupling.
In this study, phase-pure BA2MAn-1PbnI3n+1 (n = 1-3) quasi-2D PVSK microplates were successfully fabricated using the space-confined growth method. Slow crystallization effectively suppressed mixed-phase formation, producing large-area microplates with high crystallinity and naturally formed Fabry–Pérot microcavities. Among them, BA2MA2Pb3I10 (n = 3) exhibited the best crystal quality, optical properties, and well-defined cavity modes.
The exciton–photon coupling characteristics were investigated using the Lorentz oscillator model and angle-resolved reflectance (ARR) spectroscopy. Clear anti-crossing behavior confirmed the formation of exciton–polaritons. Furthermore, amplified spontaneous emission (ASE) with a threshold of approximately 0.16 mJ/cm² was observed at 77 K, demonstrating excellent optical gain.
These results demonstrate that space-confined growth provides an effective strategy for fabricating high-quality phase-pure quasi-2D PVSK microplates, offering a promising platform for low-threshold polariton lasers, polaritonic photonic devices, and coherent light sources.

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