Raman scattering enhancement of dielectric microspheres on silicon nitride film

Abstract

Circulating light in the total internal reflection within dielectric spheres or disks is called the whispering gallery mode (WGM), which by itself is highly sensitive to its surface and capable of detecting viruses and single atomic ions. The detection site of the sensors using WGM is created by the evanescent light from the circulating light inside spheres. Here we report anomalous Raman scattering enhancement in dielectric microspheres on a silicon nitride (SiN) film. This Raman enhancement occurs at the periphery of the spheres, and a similar ring of light was also observed under a fluorescence microscope. This is caused by the light circulating around the dielectric spheres as in the WGM. We observed anomalously enhanced Raman spectrum at the periphery of 3 μm diameter polystyrene (PS) microspheres on a SiN film using confocal laser Raman microscopy. The wavelength intensity of this enhanced Raman spectrum was accompanied by periodic changes due to interference. These features may lead to the development of high-sensitive sensors and optical devices.

Influence of the environment on the effect of super resonance in mesoscale dielectric spheres

“…These results are also important in understanding and explaining the super-resolution phenomena in mesoscale spherebased techniques and microscopy. Moreover, the giant field enhancement will find interesting applications in superenhanced Raman scattering [37], refractive index sensors of surrounding medium and sphere, similar to WGM [38][39][40] but with more high sensitivities, extreme and non-linear optics [13,27] and others. These effects also can be extended to the acoustic [41].…”

Studies on Femtosecond Laser Textured Broadband Anti-reflective Hierarchical a-SiNx:H Thin Films for Photovoltaic Applications

“…Silicon nitride (Si 3 N 4 ) is a key material in photonic devices, and the combination of Si 3 N 4 technology with silicon photonics and other III–V materials has opened new areas in on-chip applications . Non-stoichiometric SiNx has attracted much interest owing to its potential applications in optoelectronics technology due to its good stability and compatibility with current microelectronics technology .…”

“…39−41 Silicon nitride (Si 3 N 4 ) is a key material in photonic devices, and the combination of Si 3 N 4 technology with silicon photonics and other III−V materials has opened new areas in on-chip applications. 42 Non-stoichiometric SiNx has attracted much interest owing to its potential applications in optoelectronics technology due to its good stability and compatibility with current microelectronics technology. 43 The a-SiNx:H is exciting from the standpoint of photonics because it has several advantages, including composition tunability (from Si rich to N rich), resulting in a wide range of optical and electrical properties, as well as a broad spectral operation band from visible to infrared wavelengths.…”