Edward F. Plinski

Direct electro-optical pumping for hybrid CdSe nanocrystal/III-nitride based nano-light-emitting diodes

We propose a device concept for a hybrid nanocrystal/III-nitride based nano-LED. Our approach is based on the direct electro-optical pumping of nanocrystals (secondary excitation) by electrically driven InGaN/GaN nano-LEDs as the primary excitation source. To this end, a universal hybrid optoelectronic platform was developed for a large range of optically active nano- and mesoscopic structures. The advantage of the approach is that the emission of the nanocrystals can be electrically induced without the need of contacting them. The proof of principal was demonstrated for the electro-optical pumping of CdSe nanocrystals. The nano-LEDs with a diameter of 100 nm exhibit a very low current of ∼8 nA at 5 V bias which is several orders of magnitude smaller than for those conventionally used. The leakage currents in the device layout were typically in the range of 8 pA to 20 pA/cm2 at 5 V bias. The photon-photon down conversion efficiency was determined to be 27%. Microphotoluminescence and microelectroluminesce...

Well-ordered laser signature

Abstract It was found that the longitudinal tuning of the CO 2 laser could give a well-ordered laser signature (WOLS). The considered phenomenon was observed and investigated in an RF excited slab-waveguide CO 2 laser equipped with a confocal unstable resonator in a few configurations.

Algorithm of RF-excited slab-waveguide laser design

Basic mechanisms influencing the resonant frequency of the RF-discharged slab-waveguide CO2 laser head are described. An algorithm of calculations to design a laser head resonant frequency is given. The algorithm is experimentally confirmed.

Fourier transform in THz measurements of refractive index

A Fourier Transform is applied to the coherent detection signal in the THz photomixer arrangement. The method is used in measurements of a refractive index of plastic materials.

Limitations of the terahertz photomixer

In the paper, Fourier transform has been used for calculations of a refractive index of dielectric samples measured in the terahertz photomixer arrangement. We considered measurement limitations caused by a sampling frequency and a photomixer bandwidth.

Prediction of the thermal properties of CO2, CO, and Xe laser media

Abstract Approximation functions describing the experimental data of thermal conductivity and viscosity of chosen gases ( CO 2 , N 2 , He , Xe , CO , O 2 , Ar) are given in the paper. Introduced formulas allow to predict thermal conductivity and temperature distribution of typical high-power laser gas mixture. Examples of temperature distribution in RF excited CO2, CO, and Xe laser media are shown. Knowledge of the temperature distribution in the laser cavity can be useful for predicting the general properties of laser.

Diffractive scanning mechanism for laser marker

Abstract We present a new idea of marking based on spectral properties of CO 2 laser radiation. The idea has been illustrated on RF excited waveguide CO 2 lasers in different configurations: single channel, multi-waveguide and slab-waveguide ones. The pulse operation of the laser has been considered as well. The advantage of the presented diffraction marker is avoiding complicated and fallible mechanical elements. The only executive elements of the marker are a diffraction grating and a piezoceramic transducer. It has been shown that the slab-waveguide configuration of the RF excited CO 2 laser equipped with an unstable resonator is the most promising configuration for application to the diffraction marker.

Dynamics of spectral lines in a pulsed CO2 waveguide laser

Spectral aspects of pulse operation of RF excited CO2 waveguide lasers are presented. The hopping of emission lines were monitored and identified through the pulse duration of the laser. Syntheses of the laser total output pulse shapes were done summing of all lines taking part in oscillations.

Terahertz antenna electronic chopper

In this paper, we present an electronic circuit used to bias a photoconductive antenna that generates terahertz radiation. The working principles and the design process for the device are discussed in detail. The noise and shape of the wave measurements for a built device are considered. Furthermore, their impact on a terahertz pulse and its spectra is also examined. The proposed implementation is simple to build, robust and offers a real improvement over THz instrumentation due to the frequency tuning. Additionally, it provides for galvanic isolation and ESD protection.

Piroxicam derivatives THz classification

In this paper we report a new approach to linking the terahertz spectral shapes of drug candidates having a similar molecular structure to their chemical and physical parameters. We examined 27 newly-synthesized derivatives of a well-known nonsteroidal anti-inflammatory drug Piroxicam used for treatment of inflammatory arthritis and chemoprevention of colon cancer. The testing was carried out by means of terahertz pulsed spectroscopy (TPS). Using chemometric techniques we evaluated their spectral similarity in the terahertz range and attempted to link the position on the principal component analysis (PCA) score map to the similarity of molecular descriptors. A simplified spectral model preserved 75% and 85.1% of the variance in 2 and 3 dimensions respectively, compared to the input 1137. We have found that in 85% of the investigated samples a similarity of the physical and chemical parameters corresponds to a similarity in the terahertz spectra. The effects of data preprocessing on the generated maps are also discussed. The technique presented can support the choice of the most promising drug candidates for clinical trials in pharmacological research.