Inversionless light amplification and optical switching controlled by state-dependent alignment of molecules

We propose a method to achieve amplification without population inversion by anisotropic molecules whose orientation by an external electric field is state-dependent. It is based on decoupling of the lower-state molecules from the resonant light while the excited ones remain emitting. The suitable class of molecules is discussed, the equation for the gain factor is derived, and the magnitude of the inversionless amplification is estimated for the typical experimental conditions. Such switching of the sample from absorbing to amplifying via transparent state is shown to be possible both with the aid of dc and ac control electric fields.Comment: AMS-LaTeX v1.2, 4 pages with 4 figure

Conformity in Modern Science: An Engine of Societal Transformation?

Received 25 September 2017. Accepted 30 November 2017. Published online 18 December 2017.The penetration of science into all spheres of life has self-evidently become a contemporary “megatrend”. In turn, science itself is also undergoing distinct transformations, e.g., as a result of such processes as increasing regulation and bureaucratisation within academia. In this context, researchers as active producers of scientific knowledge face multiple challenges, including the need to cope with increasing regulation of their everyday practices. Therefore, our research purpose was to investigate the phenomenon of conformity, which, although always having been inseparable from social life, is acquiring a new significance today. Various representations of conformity (e.g. conformist behaviour) have received a great deal of attention from sociologists, biologists and psychologists; however, to our knowledge, there is no generally accepted philosophical understanding of its nature. In this paper, we provide a phenomenological study of conformity on the basis of a comprehensive literature analysis and evaluate its role as a mode of existence in modern science. For the sake of clarity, some illustrations from the everyday lives of researchers are given, including the distribution of the IMRAD format of research articles. Conformity in science is predicted to involve consequences at three distinct levels: (1) within a scientific community, when scientists follow prescribed patterns of conduct; (2) within a particular society when people from all walks of life conform to the standards set by the scientised world-view; and (3) at the global level when non-western communities conform to western standards of life through borrowing western scientific world picture

Inversionless gain in a three-level system driven by a strong field and collisions

Inversionless gain in a three-level system driven by a strong external field and by collisions with a buffer gas is investigated. The mechanism of populating of the upper laser level contributed by the collision transfer as well as by relaxation caused by a buffer gas is discussed in detail. Explicit formulae for analysis of optimal conditions are derived. The mechanism developed here for the incoherent pump could be generalized to other systems.Comment: RevTeX, 9 pages, 4 eps figure

All-cavity electromagnetically induced transparency and optical switching: semiclassical theory

The transmission of a probe field experiencing electromagnetically induced transparency and optical switching in an atomic medium enclosed in an optical cavity is investigated. Using a semiclassical input-output theory for the interaction between an ensemble of four-level atoms and three optical cavity fields coupled to the same spatial cavity mode, we derive the steady-state transmission spectra of the probe field and discuss the dynamics of the intracavity field buildup. The analytical and numerical results are in good agreement with recent experiments with ion Coulomb crystals [M. Albert et al., Nature Photon. 5, 633 (2011)].Comment: 11 pages, 9 figure

Experimental implementation of a four-level N-type scheme for the observation of Electromagnetically Induced Transparency

A nondegenerate four-level N-type scheme was experimentally implemented to observe electromagnetically induced transparency (EIT) at the $^{87}$Rb D$_{2}$ line. Radiations of two independent external-cavity semiconductor lasers were used in the experiment, the current of one of them being modulated at a frequency equal to the hyperfine-splitting frequency of the excited 5P$_{3/2}$ level. In this case, apart from the main EIT dip corresponding to the two-photon Raman resonance in a three-level $\Lambda$-scheme, additional dips detuned from the main dip by a frequency equal to the frequency of the HF generator were observed in the absorption spectrum. These dips were due to an increase in the medium transparency at frequencies corresponding to the three-photon Raman resonances in four-level N-type schemes. The resonance shapes are analyzed as functions of generator frequency and magnetic field.Comment: 3 pages, 2 figure

Autler - Townes doublet probed by strong field

This paper deals with the Autler - Townes doublet structure. Applied driving and probing laser fields can have arbitrary intensities. The explanation is given of the broadening of doublet components with the growth of probing field intensity, which was observed in experiment. The effects of Doppler averaging are discussed.Comment: 12 pages, RevTeX, 5 figures in 9 file