![]() ![]() Above this value of the gain, an unconventional mode forms, in which the phase shift after a round-trip of the light is zero. On the example of the dielectric active layer of size substantially smaller than a half-wavelength of light, we demonstrate that there is a gain at exceeding of which the change in phase due to the reflection at the layer boundaries compensates the change in phase due to propagation over the layer. ![]() Here, we provide an alternative to these two methods based on a modification of the modes of dielectric resonators by means of an active medium. The Composite Pulses approach, that is initially introduced to make the two-state quantum system robust, is also employed in the polarization manipulation which is commonly referred to be very sensitive, to make it robust and broadband, as well as to overcome its wavelength dependency.Īnalogy may also be established between two other systems: composite pulses and nonlinear frequency conversion achieved by slicing the nonlinear crystal into composite segments as a consequence of a counterintuitive implementation of flaws in well-known locations along the nonlinear crystal.įinally, as an application of the stimulated Raman adiabatic passage approach in a dissipative system, the non-Hermitian quantum system concept may be put in place to keep intensities spatially stable in a cascaded nonlinear frequency generationĮxisting methods for the creation of subwavelength resonators use either structures with negative permittivity, by exploiting subwavelength plasmonic resonances, or dielectric structures with a high refractive index, which reduce the wavelength. The similarity between the manipulation of two-state (two energy levels) quantum and two-state (electric field vectors) polarization systems is an example of such an analogy. This concept transferring between modern and classical physics is recognized as the Analogy, which is based on the examination of the similarities in mathematical formalism driving these systems. These techniques may be used in classical optics to make many sensitive classical systems robust against experimental parameters, as well as broadband, which implies they can operate over a wide spectral range. It refers to the controlled, effective, and selective excitation of an atom or molecule to a specific energy level owing to coherent quantum control schemes such as Composite Pulses, Rapid Adiabatic Passage, and Stimulated Raman Adiabatic Passage. ![]() In recent decades, quantum system manipulation has played a crucial role in a variety of modern physics disciplines, including nuclear magnetic resonance spectroscopy, quantum optics, atomic physics and quantum computation. We highlight important experimental and theoretical breakthrough results to give a comprehensive view of the current status of the field and its potential future avenues. Finally, we review a series of mechanisms which are currently available to dynamically modulate the spectrum of a thermally emitting body. After that we briefly discuss the role that spatial and temporal coherence play for thermal emission and reflect on how near- and far-field thermal emission can be measured experimentally. In this tutorial we first provide an introduction to thermal emission, with its near- and far-field description. It is the case, for example, of applications such as solar energy harvesting, thermal camouflage, radiative cooling, thermal sensing and imaging. This is achieved via an external input, which acts on the emitter and modifies its radiative behaviour. Many scenarios can benefit from a dynamic tuning of thermal emission, where such properties are modulated in real time. Clever engineering of the emitters has led to thermal radiation which can possess high degrees of angular directionality, spatial and temporal coherence, with a spectrum which can be narrow- or broadband, often overcoming the black body limit. Recent progress in the field of thermal photonics have allowed for the emergence of emission spectra which are largely distinct from the black body. The spectrum of thermal emission is conventionally associated with black body radiation.
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