COSMA: Coherent Optics Sensors for Medical Application is an European Marie Curie Project running from 2012 to March 2016, with the participation of 10 teams from Armenia, Bulgaria, India, Israel, Italy, Poland, Russia, UK, USA. The main objective was to focus theoretical and experimental research on biomagnetism phenomena, with the specific aim to develop all-optical sensors dedicated to their detection and suitable for applications in clinical diagnostics. The paper presents some of the most recent results obtained during the exchange visits of the involved scientists, after an introduction about the phenomenon which is the pillar of this kind of research and of many other new fields in laser spectroscopy, atomic physics, and quantum optics: the dark resonance.
We propose and analyze a scheme for creation of coherent superposition of meta-stable states in a multilevel
atom. The scheme is based on interaction of a frequency modulated (chirped) laser pulse and a pulse of a
constant carrier frequency with the atom having two meta-stable (ground) states and multiple excited states. The
negligible excitation of the atoms is a priority in the proposed scheme to eliminate the de-coherence processes
caused by the decay of the excited states. The scheme is applied to create coherent superposition of magnetic
sublevels of ground states of the 87Rb atom taking into account all allowed electric-dipole transitions between
magnetic sublevels of the 5 2S1/2
- 52P3/2 transition (D2 line).
In addition to the theoretical analysis we consider possible experimental realizations of the proposed
coherence creation scheme and discuss their feasibilities and constraints. We concentrate on a detection of the
superposition state in the Faraday-rotation experiment. Such detection reduces technical laser noise background
and offers high sensitivity of the coherence detection. Moreover, it allows extra control of the atomic sample and
the interaction dynamics by external magnetic field.
For the first time we have shown that increasing uniaxial pressure on the triglycine selenium single crystals leads to the
occurrence of several spectral maxima below the energy gap. It is principal that after interruption of the applied uniaxial
pressure one observes remarkable spectral shifts up to 20 nm of the principal spectral maxima at 280 nm and 340 nm.
The effect is caused by the changes of inter-molecular interactions of the van der Waals type in such kinds of crystals
and occurrence of in elastic interactions. The effect has irreversible character and after applying of uniaxial pressure
several times we see that there occur several strains which may be considered as the remaining infer-molecular stresses.
The observed phenomenon may be used for creation of the optoelectronic tensors of the pressure with the forces up to 4
kG. The performed investigations have shown that the spectral broadening is not sensitive to the pressure, however their
spectral shifts are substantially sensitive to the applied pressure. The observed effect possess a long time reversibility (up
to one month). Additional studies of piezooptical effects have shown its sensitivity to the external cw green laser light at
power 300 mW. Using the thermoluminescence we have established that the crystals are very sensitive to the number of
trapping levels within the energy gap. Additionally there were performed studies of electrooptical effects for the pulsed
10 ns Nd:YAG laser.
The paper presents a construction of an absorption instrument for measuring the flue gas smokiness. The instrument,
which was tested in industrial conditions, is a probe of the diameter 51 mm and length 2000 mm inserted into the exhaust
duct. A laser diode GaAs of the power 5 mW were used as a light source. The industrial testing was performed on Power
Unit no. 10 in the power plant TUROW II in Turoszow.
The construction and the principle of operation of an instrument introduced to the measurement of the dynamic dislocations of solid body surfaces are presented in the study. The phenomenon of speckling of laser light scattered through the rough surface was utilized. A speckle pattern was recorded by using a digitally-controlled diode matrix. Many configurations of optical arrangements for generating patterns and for mapping them into the detector plane were tested. The developed instrument can measure all components of linear and angular dislocations. The best efficiency was obtained in the measurements of the transverse component of dislocation. The range and ratio of measurement are strongly dependent on the laser light power and on the quality of the photoelement used.