The spectral sensitivity and morphological characteristics of a pyroelectric photosensor based on tetraaminodiphenyl thin films were investigated. It was found that the pyroelectric sensor sensitivity weakly depends on the radiation frequency in a wide spectral range from visible to millimeter waves and is 2...8 times higher than the sensitivity of known pyrodetectors and the Goley cell. The tetraaminodiphenyl surface morphopology has a significant roughness of up to few μm with a 1 μm film thickness. The role of the abnormal skin effect is discussed.

The spectral and amplitude-frequency characteristics of a new pyroelectric detector based on thin tetraaminodiphenyl polycyclic polymer films with a thickness of <1 mu m were studied in the electromagnetic radiation ranges of 0.4 to 10 and 300 to 3000 mu m and at local wavelengths of 81 and 100 mu m, respectively. It is shown that the volt-watt sensitivity of such a detector in the entire range is practically nonselective and is 2 to 10 times higher than the sensitivity of other pyroelectric detectors and the Golay cell. The bandwidth of the proposed pyrodetector was 330 to 500 Hz. The results showed good prospects of these sensors for fast ultrawideband spectroscopy, covering visible, infrared, terahertz, and millimeter wave ranges. (C) 2019 Society of Photo-Optical Instrumentation Engineers (SPIE)

Radiative lifetimes of 7d, 8d 1D2 excited states of Hg I are measured using pulsed two-photon excitation from the ground [Xe]5d106s21S0 mercury state, detecting the decay of the laser-induced fluorescence. The results are compared with theoretical values, obtained by means of a Hartree-Fock single configuration method, taking into account electron configuration interaction. The radiative lifetime value dependence on the effective principal quantum number for the nd 1D2 series is analyzed and compared with the quantum defect dependence.

Investigations of the behaviour of mercury transitions are reasonable task for improvement of different types light sources as well as for solving environmental problems. Recently, the time behaviour of the 546.0 nm spectral line was studied after two step pulse laser excitation of the 7(3)S state via the 6(3)P(1) state(1). A nonmonotonical decay of the population of 7(3)S was observed and was interpreted as a result of the stimulated emission in forward direction of the excitation laser beam.In our experiment we observe the nonmonotonical behaviour of the decay of the 546.0 mm spectral line intensity when the 6(3)P(1) State is excited by strong pulse laser beam. This behaviour is changing when the wavelength of excitation laser beam is tuned around the 253.6 nn wavelength.Some hypothesis for explanation of this behaviour are given.

A new experimental technique suitable for real-time measurements has been developed which permits the determination of the spatial distribution of the electron density of a plasma with a time resolution commensurate with the 6 ns duration of a single laser pulse. The accuracy and sensitivity of the electron density measurements allow the application to low-temperature plasma diagnostics. The possibilities of the method were demonstrated by studying a steady state mini-arc argon plasma at atmospheric pressure. The measured electron densities with 2 cm plasma length spanned the range from to on the plasma axis.

Investigations of the behavior of mercury transitions are reasonable tasks for improvement of different types of light sources as well as for solving environmental problems. Recently, the time behavior of the 546.0 nm spectral line was studied after two step pulse laser excitation of the 73S state via the 63P1 state. A nonmonotonical decay of the population of 73S was observed and was interpreted as a results of the stimulated emission in forward direction of the excitation laser beam. In our experiment we observe the nonmonotonical behavior of the decay of the 546.0 nm spectral line intensity when the 63P1 state is excited by strong pulse laser beam. This behavior is changing when the wavelength of excitation laser beam is tuned around the 253.6 nm wavelength. Some hypothesis for explanation of this behavior is given.