• C Y ZHAO

Articles written in Pramana – Journal of Physics

• Vernier effect of cascaded dual microring sensor

We demonstrate a Vernier microring sensor consisting of a traditional cascaded dual microring resonator and an additional measurement range unit. The sensor’s performance is simulated for different concentrations of aqueous solutions of ethylene glycol ($\rm{C_{2}H_{6}O_{2}}$). The theoretical sensitivity of our system is as high as 7386 nm/RIU, an order of magnitude much larger than that of the traditional cascaded dual microring sensor (562 nm/RIU), 13.1 times more than the traditional cascaded dual microring sensor. At the same time, the measurement range can reach as high as $2.49 × 10^{−2}$ RIU.

• Electromagnetically-induced transparency-like transmission characteristics of a waveguide coupled to a microsphere resonator

The limitation of traditional microring mode resonance, the microsphere confocal cavity is the best candidate for a low loss and controllable linewidth. Based on the transform matrix method, we investigate the waveguide coupled to a microsphere whispering-gallery mode (WGM) system. We find that the confocal cavity mode iscompletely different from the traditional ring cavity mode. The confocal cavity mode is excited in asymmetrical dual microsphere systems, and the spectrum of asymmetrical dual microsphere systems appear as an electromagnetically induced transparency (EIT)-like profile, whereas the spectrum of symmetrical dual microsphere systems appears as Lorentz profile. The traditional ring cavity mode is excited in the symmetrical single microsphere system.

• The FDTD simulation of microring feedback bend-based coupling resonator system for electromagnetically-induced transparency-like effect

A microring feedback bend-based coupling resonant system is proposed and is finite difference time domain (FDTD)-simulated to generate electromagnetically-induced transparency (EIT)-like transmission and mode distribution. The coupling between the cross-section of the waveguides gives rise to EIT-like spectrum. Most of themode field energy is concentrated in the coupling region of the feedback bend. The full-width at half-maximum(FWHM) can be tuned by controlling the gap parameter between two feedback bends. The device enables integration with some photonic devices on a chip and shows great promise in applications such as fast–slow light and optical filters.

• The Doppler shifts of resonant fluorescence spectrum for a two-level ${}^{85}$Rb atom via multiphoton Compton scattering

Usually, it is difficult to observe Compton scattering in an atom. One way to overcome this difficulty is to allow a multiphoton to collide with an atom. This phenomenon is called multiphoton Compton scattering (MCS) phenomenon. Thus, we can investigate the MCS in the visible light region. The cluster atoms move as a whole, namely atomic Dicke states, and the multiphoton interacts with cluster atoms. We can observe a significant Doppler shift of resonant fluorescence spectrum (RFS) in a room-temperature two-level ${}^{85}$Rb atomic system. In this paper, we present a detailed analysis of the physics mechanism of the Doppler shift and propose a method to measure the component of the Dicke states (the atomic polymers with different masses) by using the Doppler shift of the RFS.

• # Pramana – Journal of Physics

Volume 97, 2023
All articles
Continuous Article Publishing mode

• # Editorial Note on Continuous Article Publication

Posted on July 25, 2019