Search for: All records

For more than a decade, the linear and nonlinear optical responses of materials and composites exhibiting an epsilon-near-zero (ENZ) region have been of keen interest to the community. Among the variety of effects realized, achieving index modulation near unity on the picosecond (or less) timescale has generated the most significant impact. As a long-sought combination of strength and speed, ENZ nonlinearities have reignited interest in nonlinear processes that appear to go beyond the typical perturbative expansion (e.g., non-perturbative) as well as in time-varying nonlinear processes. Here, we aim to take a physical and intuitive look at the nonlinear index modulation in Drude-like ENZ films and highlight the physical limits of tuning. We will focus particularly on their connection (or lack thereof) with non-perturbative effects and time-varying processes and provide our opinions as to the strengths and weaknesses of ENZ films in these areas. 

Many new quantum technologies will rely on the precise manipulation of single photons; however, most light sources produce photons randomly. Quantum dots, which can reliably produce single photons, may provide a solution. From Virginia Commonwealth University and Vanderbilt University in the US, Dr Nathaniel Kinsey and Dr Justus Ndukaife are developing a device that can trap quantum dots and enhance their photon emission rates, paving the way for new quantum technologies. 

When you start a Ph.D. program, you may be thrilled to be studying a fancy topic that you love—and you should be! But don’t let that prevent you from carefully considering the impact that your Ph.D. supervisor has on your educational experience and career. To set yourself up for success, it’s worth taking the time to select someone who aligns well with your professional goals, work style and personality. 

In the continuously evolving realm of nonlinear optics, epsilon near zero (ENZ) materials have captured significant scientific interest, becoming a compelling focal point over the past decade. During this time, researchers have shown extraordinary demonstrations of nonlinear processes such as unity order index change via intensity dependent refractive index, enhanced second harmonic generation, saturable absorption in ultra-thin films and more recently, frequency shifting via time modulation of permittivity. More recently, remarkable strides have also been made in uncovering the intricacies of ENZ materials' nonlinear optical behavior. This review provides a comprehensive overview of the various types of nonlinearities commonly observed in these systems, with a focus on Drude based homogenous materials. By categorizing the enhancement into intrinsic and extrinsic factors, it provides a framework to compare the nonlinearity of ENZ media with other nonlinear media. The review emphasizes that while ENZ materials may not significantly surpass the nonlinear capabilities of traditional materials, either in terms of fast or slow nonlinearity, they do offer distinct advantages. These advantages encompass an optimal response time, inherent enhancement of slow light effects, and a broadband characteristic, all encapsulated in a thin film that can be purchased off-the shelf. The review further builds upon this framework and not only identifies key properties of transparent conducting oxides that have so far made them ideal test beds for ENZ nonlinearities, but also brings to light alternate material systems, such as perovskite oxides, that could potentially outperform them. We conclude by reviewing the upcoming concepts of time varying physics with ENZ media and outline key points the research community is working toward. 

To address the challenges of developing a scalable system of an on-chip integrated quantum emitter, we propose to leverage the loss in our hybrid plasmonic-photonic structure to simultaneously achieve Purcell enhancement as well as on-chip maneuvering of nanoscale emitter via optical trapping with guided excitation-emission routes. In this report, we have analyzed the feasibility of the functional goals of our proposed system in the metric of trapping strength (∼8K_BT), Purcell factor (>1000∼), and collection efficiency (∼10%). Once realized, the scopes of the proposed device can be advanced to develop a scalable platform for integrated quantum technology. 

Plasmonic-based integrated nanophotonic modulators, despite their promising features, have one key limiting factor of large insertion loss (IL), which limits their practical potential. To combat this, we utilize a plasmon-assisted approach through the lens of surface-to-volume ratio to realize a 4-slot based EAM with an extinction ratio (ER) of 2.62 dB/µm and insertion loss (IL) of 0.3 dB/µm operating at ∼1 GHz and a single slot design with ER of 1.4 dB/µm and IL of 0.25 dB/µm operating at ∼20 GHz, achieved by replacing the traditional metal contact with heavily doped indium tin oxide (ITO). Furthermore, our analysis imposes realistic fabrication constraints, and material properties, and illustrates trade-offs in the performance that must be carefully optimized for a given scenario. 

On the occasion of 60 years of nonlinear-optical research, we present new data tables listing nonlinear- optical properties for different material categories as reported in the literature since 2000, and provide best practices for performing experiments. 

Data usage across the internet is growing exponentially, fueled primarily by the move to cloud computing and penetration of streaming services into developing countries. To address the growing energy needs of data centers, we propose an all oxide plasmon assisted electro-optic modulator, which features enhanced light-matter interaction, and compact sizes as seen in plasmonic modulators while at the same time maintaining low insertion losses, as seen in photonic modulators. This is achieved by utilizing a device design that selectively engages and disengages the lossy plasmonic component, as the device switches from low transmission to high transmission modes.