We theoretically demonstrate coherent control over propagation of surface plasmon polaritons(SPP), at both telecommunication and visible wavelengths, on a metallic surface adjacent to quantum coherence (phaseonium) medium composed of three-level quan
tum emitters (semiconductor quantum dots, atoms, rare-earth ions, etc.) embedded in a dielectric host. The coherent drive allows us to provide sufficient gain for lossless SPP propagation and also lowers the pumping requirements. In case of lossy propagation, an order of magnitude enhancement in propagation length can be achieved. Optical control over SPP propagation dynamics via an external coherent drive holds promise for quantum control in the field of nanophotonics.
Quantum coherence and interference effects in atomic and molecular physics has been extensively studied due to intriguing counterintuitive physics and potential important applications. Here we present one such application of using quantum coherence t
o generate and enhance gain in extreme ultra-violet(XUV)(@58.4nm in Helium) and infra-red(@794.76nm in Rubidium) regime of electromagnetic radiation. We show that using moderate external coherent drive, a substantial enhancement in the energy of the lasing pulse can be achieved under optimal conditions. We also discuss the role of coherence. The present paper is intended to be pedagogical on this subject of coherence-enhanced lasing.
We propose an efficient scheme for the generation and the manipulation of Raman fields in an homogeneously broadened atomic vapor in a closed three levels $Lambda$-configuration. The key concept in generating the Raman and sub-Raman fields efficientl
y at lower optical densities involve the microwave induced atomic coherence of the lower levels. We show explicitly that, generation efficiency of the Raman fields can be controlled by manipulating the coherences via phase and amplitude of the microwave field.
Ultralow-power diode-laser radiation is employed to induce photodesorption of cesium from a partially transparent thin-film cesium adsorbate on a solid surface. Using resonant Raman spectroscopy, we demonstrate that this photodesorption process enabl
es an accurate local optical control of the density of dimer molecules in alkali-metal vapors.
We present an experimental and theoretical study of phase-dependent interference effects in multi-photon excitation under bichromatic radio-frequency (rf) field. Using an intense rf pulse, we study the interference between the three-photon and one-ph
oton transition between the Zeeman sub-levels of the ground state of $^{87}$Rb that allows us to determine the carrier-envelope phase of the fields even for long pulses.
Using a recently developed technique to solve Schrodinger equation for constant mass, we studied the regime in which mass varies with position i.e position dependent mass Schrodinger equation(PDMSE). We obtained an analytical solution for the PDMSE a
nd applied our approach to study a position dependent mass $m(x)$ particle scattered by a potential $mathcal{V}(x)$. We also studied the structural analogy between PDMSE and two-level atomic system interacting with a classical field.
