Microcavity enhancement of low‐frequency Raman scattering from a CsPbI3 thin film. (27th August 2019)

• Record Type: Journal Article
• Authors: Uliel, Tal Ben; Gouda, Laxman; Aviv, Hagit; Itzhak, Anat; Tischler, Yaakov R.
• Is Part Of: Journal of Raman spectroscopy. Volume 50:Number 11(2019)
• Page Start: 1672
• Page End: 1678
• Publication Date: 2019-08-27
• Subjects: cavity resonance peak -- CsPbI3 -- DBR microcavity -- low‐frequency Raman -- signal enhancement; Raman spectroscopy -- Periodicals; 535.846
• DOI: 10.1002/jrs.5715
• Languages: English
• ISSNs: 0377-0486

Abstract

Abstract: Low‐frequency Raman (LFR) spectroscopy is a powerful, nondestructive method used for chemical and structural characterization of materials. Typically, the signal intensity of LFR is relatively low, resulting significantly longer signal acquisition duration. Here, we show a photonic structure based on a planar optical microcavity consists of two distributed Bragg reflectors that is capable of enhancing the LFR signal of the material placed in between the mirrors. CsPbI3 forms smooth and uniform thin films and has distinct LFR signatures; thus, we chose to use it for investigating the microcavity enhancement capabilities. By compromising the quality factor of the cavity, we achieved a broader transmission peak and essentially earned enhancement from the double‐resonance effect. Measurements on a CsPbI3 thin film inside a cavity compared with a bare film spin coated on glass demonstrated two orders of magnitude enhancement. In addition, we fabricated the microcavity with a gradient in the resonance wavelength, in order to study the tuning effect on spectral features and on the enhancement factor. Our results show that microcavity is a promising device for enhancing LFR scattering signal and for sensitive characterization of nanomaterials. Abstract : The graphical abstract describes the LFR scattering enhancement by introducing the goal material inside a microcavity. The distance between the two DBR mirrors is designed for dual trapping of the exciting laser and the LFR region providing a more significant enhancement. In addition, for selective enhancement of a specific spectral region, a tunable microcavity was fabricating.