Ambient Pressure Sublimation Technique Provides Polymorph‐Selective Perylene Nonlinear Optical Microcavities. Issue 1 (21st November 2019)

• Record Type: Journal Article
• Authors: Pradeep, Vuppu Vinay; Mitetelo, Nikolai; Annadhasan, Mari; Popov, Mikhail; Mamonov, Evgeniy; Murzina, Tatiana; Chandrasekar, Rajadurai
• Is Part Of: Advanced optical materials. Volume 8:Issue 1(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-11-21
• Subjects: nonlinear optics -- optical microcavities -- organic photonics -- perylene -- sublimation techniques; Optical materials -- Periodicals; Photonics -- Periodicals; 620.11295
• DOI: 10.1002/adom.201901317
• Languages: English
• ISSNs: 2195-1071

Abstract

Abstract: Highly pure, organic, crystalline materials with nonlinear optical (NLO) properties are in great demand due to their potential to be utilized in miniaturized nanophotonic device applications. Perylene dye is one of the celebrated near‐direct bandgap NLO materials. It crystallizes in two distinctive polymorphic forms (square‐shaped, α, and rhombus‐shaped, β) emitting yellow and green fluorescence, respectively. However, selective access to any one of the polymorphic microcrystals possessing qualities such as smooth‐surface and mirror‐like light‐reflecting sharp edges is a challenging task. On the other hand, these qualities are indispensable for a microcrystal to operate as an optical cavity. Here, a cost‐effective and straightforward, yet promising sublimation technique to grow microscale perylene crystals with the above qualities in a polymorph‐selective manner at ambient pressure is presented. As a result, both polymorphic microcrystals act as whispering gallery mode (WGM) cavities in the linear and notably, NLO regime as well. In agreement with the experiments, finite difference time domain numerical calculations support the WGM‐cavity‐type and also reveal the intricate localization of electric‐field within these cavities. Further, the quadratic dependence of emission intensity as a function of laser power establishes the two‐photon absorption nature of the optical cavities pumped by infrared lasers. Abstract : Ambient pressure sublimation technique effectively grows polymorph‐selective organic photonic microcrystals in a controlled manner. As a proof of principle, high‐quality microcrystals of a and b phase perylene are grown selectively at a specific temperature range. Interestingly, these microcrystals display outstanding one‐ and two‐photon pumped vivid luminescence, and also act as photonic cavities demonstrating the practical usefulness of the growth technique.