Chirped Pulse Control of Raman Coherence in Atoms and Molecules

A novel chirped pulse control scheme is presented based on Coherent Anti-Stokes Raman Spectroscopy (C-CARS) aiming at maximizing the vibrational coherence in atoms and molecules. The scheme utilizes chirping of the three incoming pulses, the pump, the Stokes and the probe, in the four-wave mixing process of C-CARS to fulfill the adiabatic passage conditions. The derivation of the scheme is based on simplifying the four-level system into a 'super-effective' two level system via rotating wave approximation and adiabatic elimination of the excited state manifold. The robustness, spectral selectivity and adiabatic nature of C-CARS method may prove useful for sensing, imaging, and detection. It is demonstrated that the selectivity in excitation of vibrational degrees of freedom can be controlled by carefully choosing the spectral chirp rate of the pulses. The C-CARS control scheme is applied to a surrogate methanol molecule to generate an optimal anti-Stokes signal backscattered from a cloud of molecules a kilometer away. The theory is based on the solution of the coupled Maxwell-Liouville von Neumann equations and focuses on the quantum effects induced in the target molecules by the control pulse trains. The propagation effects of pulses through the medium are evaluated and the buildup of the molecular-specific anti-Stokes signal is demonstrated numerically. A deep learning technique, using Convolutional Neural Networks (CNN), is implemented to characterize the control pulses and evaluate time-dependent phase characteristics from them. The effects of decoherence induced by spontaneous decay and collisional dephasing are also examined. Additionally, we present the technique of Fractional Stimulated Raman Adiabatic Passage (F-STIRAP) and demonstrate that it can be utilized for remote detection in a multi-level system by creation of a maximally coherent superposition state

Control with EIT: High energy charged particle detection

The strong non-linear optical response of atomic systems in electromagnetically induced transparency (EIT) states is considered as a means to detect the presence of small perturbations to steady states. For the 3-level system, expressions for the group velocity and group velocity dispersion (GVD) were derived and a quantum control protocol was established to account for the change in the chirp spectrum of a probe pulse when the steady state was perturbed. This was applied to the propagation of slow Cherenkov polaritons in the medium due to the passage of a train of high-energy charged particles (high energy particles). The choice of the initial steady state with focus on the slow light condition and strong narrowly confined dispersion, equated to the continuous trapping of Cherenkov polaritons in the medium along a narrow group cone, allowing for non-trivial fields to accumulate. Considering another medium prepared for the detection of the radiation, sweeping of the control field and detuning parameters in the field-atom parameter space showed the presence of optimal regions to maximize the first order perturbation in the coherences creating changes in the optical responses that modify the chirp spectra of probe pulses.Comment: 32 pages, 9 figure

Stimulated Raman Adiabatic Passage (STIRAP) as a Route to Achieving Optical Control in Plasmonics

Optical properties of ensembles of three-level quantum emitters coupled to plasmonic systems are investigated employing a self-consistent model. It is shown that stimulated Raman adiabatic passage (STIRAP) technique can be successfully adopted to control optical properties of hybrid materials with collective effects present and playing an important role in light-matter interactions. We consider a core-shell nanowire comprised of a silver core and a shell of coupled quantum emitters and utilize STIRAP scheme to control scattering efficiency of such a system in a frequency and spatial dependent manner. After the STIRAP induced population transfer to the final state takes place, the core-shell nanowire exhibits two sets of Rabi splittings with Fano lineshapes indicating strong interactions between two different atomic transitions driven by plasmon near-fields.Comment: 11 pages, 6 figures, accepted, Physical Review

Chirped Fractional Stimulated Raman Adiabatic Passage

Stimulated Raman Adiabatic Passage (STIRAP) is a widely used method for adiabatic population transfer in a multilevel system. In this work, we study STIRAP under novel conditions and focus on the fractional, F-STIRAP, which is known to create a superposition state with the maximum coherence. In both configurations, STIRAP and F-STIRAP, we implement pulse chirping aiming at a higher contrast, a broader range of parameters for adiabaticity, and enhanced spectral selectivity. Such goals target improvement of quantum imaging, sensing and metrology, and broaden the range of applications of quantum control techniques and protocols. In conventional STIRAP and F-STIRAP, two-photon resonance is required conceptually to satisfy the adiabaticity condition for dynamics within the dark state. Here, we account for a non-zero two-photon detuning and present control schemes to achieve the adiabatic conditions in STIRAP and F-STIRAP through a skillful compensation of the two-photon detuning by pulse chirping. We show that the chirped configuration - C-STIRAP - permits adiabatic passage to a predetermined state among two nearly degenerate final states, when conventional STIRAP fails to resolve them. We demonstrate such a selectivity within a broad range of parameters of the two-photon detuning and the chirp rate. In the C-F-STIRAP, chirping of the pump and the Stokes pulses with different time delays permits a complete compensation of the two-photon detuning and results in a selective maximum coherence of the initial and the target state with higher spectral resolution than in the conventional F-STIRAP

Congenital and Acquired Interferonopathies: Differentiated Approaches to Interferon Therapy

This chapter reviews various interferon (IFN) system disturbances—interferonopathies. The authors describe clinical specifics of type I interferonopathy associated with overexpression of IFNα—which is a rare Mendelian genetic disease. Certain autoimmune diseases (systemic lupus erythematosus (SLE), vasculitis, immune dysregulation syndrome, etc.) are also characterized by overproduction of IFNα. Furthermore the most common interferonopathies are described—deficiencies of IFN, congenital or acquired IFNα/IFNβ and IFNγ deficiencies in children and adults. Deficiency of IFNα/IFNβ associated with severe recurrent viral infections and deficiency of IFNγ cause mycobacterial infection. Interferon-corrective therapy methods are described. The target therapy of type I interferonopathies (biologics) binds IFNα and normalizes the high level of IFNα. From the other side, patients with congenital IFNα deficiencies are needed in replacement IFN therapy. In case of acquired IFNα deficiency, the differentiated interferon-corrective therapy is performed. In both replacement and interferon-corrective therapies, recombinant human IFNα2b in complex with antioxidants (Viferon®) can be used, because their application is safe and has good clinical efficiency and no side effects

Mirrorless lasing: a theoretical perspective

Mirrorless lasing has been a topic of particular interest for about a decade due to promising new horizons for quantum science and applications. In this work, we review first-principles theory that describes this phenomenon, and discuss degenerate mirrorless lasing in a vapor of Rb atoms, the mechanisms of amplification of light generated in the medium with population inversion between magnetic sublevels within the $D_2$ line, and challenges associated with experimental realization

Ribosomal DNA as DAMPs Signal for MCF7 Cancer Cells

Introduction: The cell free ribosomal DNA (cf-rDNA) is accrued in the total pool of cell free DNA (cfDNA) in some non-cancer diseases and demonstrates DAMPs characteristics. The major research questions: (1) How does cell free rDNA content change in breast cancer; (2) What type of response in the MCF7 breast cancer cells is caused by cf-rDNA; and (3) What type of DNA sensors (TLR9 or AIM2) is stimulated in MCF7 in response to the action of cf-rDNA?Materials and Methods: CfDNA and gDNA were isolated from the blood plasma and the cells derived from 38 breast cancer patients and 20 healthy female controls. The rDNA content in DNA was determined using non-radioactive quantitative hybridization. In order to explore the rDNA influence on MCF7 breast cancer cells, the model constructs (GC-DNAs) were applied: pBR322-rDNA plasmid (rDNA inset 5836 bp long) and pBR322 vector. ROS generation, DNA damage, cell cycle, expression of TLR9, AIM2, NF-kB, STAT3, and RNA for 44 genes affecting the cancer cell viability were evaluated. The methods used: RT-qPCR, fluorescent microscopy, immunoassay, flow cytometry, and siRNA technology.Results: The ratio R = cf-rDNA/g-rDNA for the cases was higher than for the controls (median 3.4 vs. 0.8, p < 10−8). In MCF7, GC-DNAs induce a ROS burst, DNA damage response, and augmentation of NF-kB and STAT3 activity. The number of the apoptotic cells decreases, while the number of cells with an instable genome (G2/M– arrest, micronuclei) increase. Expression of anti-apoptotic genes (BCL2, BCL2A1, BCL2L1, BIRC3, MDM2) is elevated, while expression of pro-apoptotic genes (BAX, BID, BAD, PMAIP1, BBC3) is lowered. The cells response for pBR322-rDNA is much more intense and develops much faster, than response for pBR322, and is realized through activation of TLR9- MyD88 - NF-kB- signaling. This difference in response speed is owing to the heightened oxidability of pBR322-rDNA and better ability to penetrate the cell. Induction of TLR9 expression in MCF7 is followed by blocking AIM2 expression.Conclusion: (1) Ribosomal DNA accumulates in cfDNA of breast cancer patients; (2) Cell free rDNA induce DNA damage response and stimulates cells survival, including cells with an instable genome; (3) Cell free rDNA triggers TLR9- MyD88- NF-kB- signaling, with significantly repressing the expression of AIM2

Abstracts from the 20th International Symposium on Signal Transduction at the Blood-Brain Barriers

https://deepblue.lib.umich.edu/bitstream/2027.42/138963/1/12987_2017_Article_71.pd