We report a proof-of-principle experiment where the refractive index of an atomic vapor is enhanced while maintaining vanishing absorption of the beam. The key idea is to drive alkali atoms in a vapor with appropriate control lasers and induce a gain resonance and an absorption resonance for a probe beam in a two-photon Raman configuration. The strength and the position of these two resonances ...

objective: exposure to mercury can occur in occupational and environmental settings. during clinical work with dental amalgam, the dental personnel are exposed to both metallic mercury and mercury vapor. the aim of the present study was to investigate blood mercury level (bml) and its determinants among dentists practicing in hamadan city, iran. materials and methods: this cross sectional study...

In recent years, the characterization of radiation falling within so-called “terahertz (THz) gap” has become an ever more prominent issue due to increasing use THz systems in applications such as nondestructive testing, security screening, telecommunications, and medical diagnostics. detection technologies have advanced rapidly, yet traceable calibration remains challenging. this paper, we demo...

Extensive distribution of hazardous substances in food chain and the deleterious effect of their residues on public health are a great concern of the society. Chicken eggs, as one of the most popular food commodities, in different parts of Tehran (Iran) were analyzed for two groups of hazardous substances including some organochlorine pesticides (OC) such as aldrin, lindane, dieldrin, dichlorod...

IN CONVENTIONAL atomic absorption spectrophotometry a solution of the sample is introduced into the flame as an aerosol by means of a nebulizer. However, commercial nebulizers are only about 5 efficient in forming fine droplets suitable for atomization by the flame ( I ) . Furthermore, a solution aspirated at a usual rate of 3-5 ml/min for about 10 sec produces a concentration signal extending ...