Use of hot atomic vapor as a new tool for tracing the complex nature of light has become a knowledge-based topic in recent years. In this paper, we examine the polarization ellipse of the Bloch surface wave (BSW) through the effect of a magnetic field on the coupling of these surface waves in BSW-hot atomic vapor cell. For this purpose, we fabricate a one-dimensional photonic crystal-based Bloch wave atom cell, where under different configurations of magnetic field, polarization ellipse of Bloch surface waves has been recorded experimentally. Our results indicate that by applying the magnetic field in different directions, Faraday and Voigt, the characteristics of electromagnetically induced transparency (EIT-like) of hybrid system change. We have used these changes to redefine the geometry of Voigt and Faraday for evanescent waves, as well as to measure the ratio of the components of the elliptical polarized electric field. These characterizations can open new insight into the miniaturized atomic field in high quality and low volumetric areas.
Quantitative assessment of polarization properties of waves opens up the way for effective exploitation of them in many amazing applications. Tamm surface waves (TSW) that propagate on the interface of periodic dielectric media are proposed for many applications in numerous reports. The polarization state of TSW is not simply intuitive and would not be extracted from reflection spectra. Here considering orientation sensitive nature of the interaction between polarized electromagnetic wave and atom, we try to quantitatively characterize the polarization state of TSWs, excited on the surface of the 1D photonic crystal. To do this we performed direct contact between TSW and rubidium atomic gas by fabrication of a one-dimensional photonic crystal-atomic vapor cell and applied a moderate external magnetic field to create geometrical meaning and a sense of directionality to dark lines in reflection intensity. Our experimental results indicate that transition lines in the reflection spectrum of our hybrid system modify dependent on the orientation of the applied magnetic field and the transverse spin of TSW. We have used these changes to redefine the geometry of Voigt and Faraday for evanescent waves, especially Tamm surface waves. In the end, we performed simple mathematical operations on absorption spectra and extract the ratio of longitudinal and transverse electric field components of the polarization vector of TSW equal to [Formula: see text].
Considering efforts for hot atomic vapor-nanophotonics integration as a new paradigm in quantum optics, in this paper, we introduce 1D photonic crystal-Rb vapor cell as structure with miniaturized interaction volume. The Bloch surface wave (BSW) excited on surface of a photonic crystal as electromagnetic hosting photonic mode, and altered the optical response of Rb atoms in the vicinity of surface. Coupling of atomic states with BSW confined modes would lead to quantum interference effects and results in nonlinearities in resonant coupling of atoms with BSW. We show Bloch surface wave induced transparency is highly stable under a change of incidence angle. Our results show slight changes in transitions detuning's due to nonlinear interactions like the Casimire-Polder effect under change of localized density of optical states.
Various efforts have been made to determine the polarization state of evanescent waves in different structures. The present study shows the reliability of magneto-optical spectroscopy of D1 and D2 lines of rubidium metal and polarization-dependent transitions to investigate and trace the changes in the polarization state of evanescent fields during total internal reflection over different angles. For this purpose, we design and fabricate atomic- evanescent Rb vapor cells and examine the effect of polarization changes of evanescent waves, depending on the propagation direction of evanescent waves in anisotropic rubidium vapor media under 88 mT external magnetic field by different configurations theoretically and experimentally. The results confirm the dependency of allowed [Formula: see text] transitions on the magneto optical configuration as a tool to determine changes in the polarization of evanescent waves in more complicated wave states in anisotropic media.
Magnetic-free nonreciprocal optical devices have attracted great attention in recent years. Here, we investigated the magnetic-free polarization rotation of light in an atom vapor cell. Two mechanisms of magnetic-free nonreciprocity have been realized in ensembles of hot atoms, including electromagnetically induced transparency and optically-induced magnetization. For a linearly polarized input probe light, a rotation angle up to 86.4° has been realized with external control and pump laser powers of 10 mW and is mainly attributed to the optically-induced magnetization effect. Our demonstration offers a new approach to realize nonreciprocal devices, which can be applied to solid-state atom ensembles and may be useful in photonic integrated circuits.
Research of hot atomic vapor systems has a long history. Recently, much-improved technologies, such as lasers, microwaves and digital/analog control systems, have led to exciting progress in this reviving field. Due to its cryogenic-free and vacuum-free deployment potential, room-temperature and quantum-enabled sensing devices using gaseous atoms have become a popular research topic, and engineering such devices has received considerable attention. Proof-of-principle experiments have been performed demonstrating new ideas such as quantum-enhanced motion sensors, next-generation magnetometers, Rydberg enabled microwave sensors, etc. This thesis focuses on my work related to electromagnetic-field sensing using Rydberg atoms in vapor cells, where Rydberg atoms are excited and detected by electromagnetically induced transparency (EIT) spectroscopy. I first investigate the detection of strong magnetic fields (
sim 1~T) in the Paschen-Back regime. The diamagnetic (quadratic) response of the Rydberg levels makes the atoms sensitive to small fluctuations in field strength on a large background. By implementing an isotope-mixed cell, we demonstrate that accurate measurement, within a relative uncertainty of
pm0.12%. Many Rydberg-enabled radio frequency and microwave sensing applications require a capability of zeroing or intentional tuning of small DC electric fields inside the vapor cell. For this purpose, I explore an in-situ DC electric-field sensing and tuning method without using any bulk or thin film electrodes. I find that the photoelectric effect on the vapor cell walls (with invisible, atomic Rb aggregate layers covering the surfaces) can generate tuning fields up to 0.8~V/cm, with an inhomogeneity of about 2%. The spatial distribution of these fields can be directly monitored by quadratic Stark shifts of the Rydberg atoms. This work may inspire new approaches for DC-field control in miniaturized, metal-free atomic vapor-cell devices. Like many other quantum measurements on hot gaseous samples, short interaction time and other technical decoherence processes are the major factors which limit the precision and, in certain cases, the accuracy of the metrological results. In order to study these effects in the context of EIT, I performed an EIT experiment using a
Lambda-type quantum system consisting of the hyperfine ground states and the first excited electronic state of the Rb atoms contained in a buffer-gas-free thermal vapor cell without anti-relaxation coating. Technical line-broadening effects due to inhomogeneity of stray magnetic fields, laser frequency jitter, transverse beam intensity distribution, interaction time distribution, and atom-wall/impurity gas collisions are studied. Experimental results and numerical simulations are compared. These results provide crucial information and quantitative insights for vapor cell sensor design. The development of compact and multi-functional spectroscopy vapor cells is widely considered to be a critical engineering step towards manufacturing field-deployable sensors for real life applications. My R&D efforts towards fabrication of glass spectroscopy cells with integrated, highly-conductive silicon components are presented in the last part of my thesis. I explored various technical challenges and successfully developed a proof-of-principle prototype from scratch. The device allows the application of electric fields inside the cell for particle trapping and for tuning Rydberg transitions. Further, the highly-conductive silicon components enable microwave polarization filtering for microwave sensing applications, plasma-physics studies, etc. Preliminary experimental/technical data and simulations are presented. In summary, in my thesis I report on a comprehensive study of several spectroscopic and field sensing applications of Rydberg and ground-state atoms in vapor cells, as well as forays into novel methods to engineer vapor cells with embedded electrodes.
Recently, there is growing interest in integrating alkali vapors with nanoscale photonic structures, such as nano-waveguides, resonators and nanoantennas. Nanoscale confinement of electromagnetic fields may introduce a longitudinal electric field component, giving rise to circularly polarized modes which are essential for diverse applications involving vapor and light, such as chirality and non-reciprocity. Hereby, we have designed, fabricated and characterized a miniaturized vapor cell that is integrated with optical waveguides that are designed to generate a peculiar circular-like polarization. Taking advantage of this phenomenon, we demonstrate a spectral shift in the atomic absorption signatures at varying magnetic fields, and significant isolation between forward and backward propagating waves in our atomic-cladded waveguide. Our results pave the way for the utilization of chip-scale integrated atomic devices in applications such as optical isolation and high spatial resolution magnetometry.