Neon Laser Research Articles

Visible and Ultraviolet Plasma Lines of the He–Ne Gas Laser

A study of helium–neon laser plasma lines was done using a double grating spectrometer and a helium-neon laser with an emission wavelength of 632.8 nm (15 802 cm−1). The absolute wavenumber, measured to within [Formula: see text]0.2 cm−1, and wavelength of each plasma line are presented, along with intensity and shift relative to the main laser line. Several of the measured lines have not been reported in the literature and are observed at shifts between 0 and 1500 cm−1 from the laser line, a spectral region commonly probed by optical Raman scattering experiments. Accounting for the possibility of second-order diffraction permitted many previously unassigned lines to be attributed to known neon electronic transitions with wavelengths in the ultraviolet region of the electromagnetic spectrum.

Power stability of different lasers and its effect on the outcome of phase-stepping shearography experiments

We examined the effect and influence of power stability of different commonly used lasers on the outcome of phase-stepping shearographic experiments. We performed power stability measurements with three different lasers (helium–neon laser, red diode laser and green frequency-doubled neodymium laser). We subsequently performed phase-stepping shearography experiments using these lasers as light sources. We found a correlation with the quality of the shearograms and the power stability of the lasers. This enables us to compare the suitability of various lasers for phase-stepping shearography experiments and to choose the best laser for this application.

Effects of intravascular photobiomodulation on cognitive impairment and crossed cerebellar diaschisis in patients with traumatic brain injury: a longitudinal study

The association between intravascular photobiomodulation (iPBM) and crossed cerebellar diaschisis (CCD) and cognitive dysfunction in patients with traumatic brain injury (TBI) remains unknown. We postulate that iPBM might enable greater neurologic improvements. The objective of this study was to evaluate the clinical impact of iPBM on the prognosis of patients with TBI. In this longitudinal study, patients who were diagnosed with TBI were recruited. CCD was identified from brain perfusion images when the uptake difference of both cerebella was > 20%. Thus, two groups were identified: CCD( +) and CCD( −). All patients received general traditional physical therapy and three courses of iPBM (helium–neon laser illuminator, 632.8 nm). Treatment assemblies were conducted on weekdays for 2 consecutive weeks as a solitary treatment course. Three courses of iPBM were performed over 2–3 months, with 1–3 weeks of rest between each course. The outcomes were measured using the Rancho Los Amigos Levels of Cognitive Functioning (LCF) tool. The chi-square test was used to compare categorical variables. Generalized estimating equations were used to verify the associations of various effects between the two groups. p < 0.05 indicated a statistically significant difference. Thirty patients were included and classified into the CCD( +) and CCD( −) groups (n = 15, each group). Statistics showed that before iPBM, CCD in the CCD( +) group was 2.74 (exp 1.0081) times higher than that of CCD( −) group (p = 0.1632). After iPBM, the CCD was 0.64 (exp-0.4436) times lower in the CCD( +) group than in the CCD( −) group (p < 0.0001). Cognitive assessment revealed that, before iPBM, the CCD( +) group had a non-significantly 0.1030 lower LCF score than that of CCD( −) group (p = 0.1632). Similarly, the CCD( +) group had a non-significantly 0.0013 higher score than that of CCD( −) after iPBM treatment (p = 0.7041), indicating no significant differences between the CCD( +) or CCD( −) following iPBM and general physical therapy. CCD was less likely to appear in iPBM-treated patients. Additionally, iPBM was not associated with LCF score. Administration of iPBM could be applied in TBI patients to reduce the occurrence of CCD. The study failed to show differences in cognitive function after iPBM, which still serves as an alternative non-pharmacological intervention.

Neon lasing (λ = 540.1 nm) in a dense optical cavity pumped by a pulsed inductive cylindrical discharge

The experimental results of the lasing characteristics dependence of the inductive neon laser (λ = 540.1 nm) on the optical cavity quality factor are presented. In the described experiments, the laser was operated in the amplified spontaneous emission mode. A frontal-substrate resonator (made according to the type of an open Fabry–Perot interferometer) was used, as well as a dense resonator with a reflection coefficient of the front mirror of 82%. Replacing the front substrate with an output mirror resulted in an increase in the lasing energy and optical pulse duration from 8.5 μJ to 41 μJ and from 10.0 ± 0.1 ns to 14.8 ± 0.1 ns, respectively. It is shown that the use of a dense resonator allows us to change the shape of the laser beam in the far field from annular to circular and to obtain intensity distribution close to uniform.

Simulation and Characterization of Optical Cavity for Iodine Stabilized Helium Neon Laser

Simulation and Characterization of Optical Cavity for Iodine Stabilized Helium Neon Laser

Influence of Laser Irradiation on the Mechanism of Viscous Flow of Aqueous Sodium Chloride Solution

The effect of 632.8-nm radiation of a helium–neon laser on the viscosity of an aqueous sodium chloride solution has been studied. It has been shown that irradiation changes the nature and numerical values of the concentration dependence of viscosity. The concentration dependences of the viscous-flow activation energy for unirradiated and irradiated aqueous sodium chloride solutions have been determined. The influence of irradiation on the parameters of the power-law dependence of the solution viscosity on concentration has been analyzed, and the temperature dependences of these parameters have been determined. It has been concluded that laser irradiation alters the structural organization of the aqueous system and reduces

Neon Laser with Wavelengths of 540.1 and 614.3 nm Pumped by a Pulsed Inductive Cylindrical Discharge

Neon Laser with Wavelengths of 540.1 and 614.3 nm Pumped by a Pulsed Inductive Cylindrical Discharge

Pre-Sowing Laser Light Stimulation Increases Yield and Protein and Crude Fat Contents in Soybean

Pre-sowing laser light stimulation is a method commonly used to increase the productivity of legume species. However, it has not been proved that single-laser light stimulation is a more effective technique for enhancing plant productivity and seed yield quality than using different laser lights in sequence, by which means synergistic relations are produced. A two-year, single-factor field experiment was performed in order to test selected combinations of light stimulation of soybean seeds, the effectiveness of which would be expressed as increased plant yield and improved quality parameters. Pre-sowing light stimulation of soybean seeds was shown to significantly influence the morphological traits of the plants. It significantly increased pod number, pod weight, seed number, and seed weight compared to the control. Coherent laser light stimulation of soybean seeds with a helium–neon laser and with an argon laser increased soybean yields by 30% on average compared to the control. The ratio of the yield from the main shoot to the yield from the lateral branches in this treatment was 40:60, indicating that pre-sowing stimulation of seeds had a significant and positive effect by increasing the yield of the lateral branches relative to the control. Stimulation of seeds (3 × 3 s) with a helium–neon laser significantly increased protein content in soybean seeds, on average by 11% compared to the control. A longer duration of pre-sowing stimulation of seeds (3 × 9 s) resulted in a significant increase in crude fat content in the seeds by an average of 5% compared to the control. The use of physical light stimulation on soybean seeds is a promising solution for increasing soybean yields.

Visualization of hydrogen jet using deformation of the laser beam profile

Hydrogen has the widest flammable range, the fastest flame propagation speed, and the lowest ignition energy, so its safety needs special attention before the wide application of hydrogen energy. The main objective of this work is to propose a new method to evaluate hydrogen jet pressure by using a Helium–Neon laser through the jet. A mathematical model was proposed, which describes the deformation of the laser beam profile passing through an axisymmetric circular hydrogen jet pressure flow field in detail. This research attempts to apply the expression of density Gaussian distribution, ideal gas equation, and Gladstone Dale equation to disclose the deformation of laser beam profile under different outlet conditions. The experimental uncertainty is about 3 × 10−3. A non-contact optical experimental system is established to visually measure the density gradient distribution of the gas jet. Our findings show that the hydrogen jet can be regarded as a gas-phase lens, and the deformation of the laser beam profile in the horizontal direction increases linearly with jet pressure. Finally, the preliminary results of calculations of the spot area with the theoretical model were presented and compared with the images of the laser beam profile passing through the jet in the experiment. The theoretical model gave similar results and the overall agreement with the experiment was satisfactory. Our technology exhibits high sensitivity in the measurement of hydrogen leakage pressure, providing a theoretical basis for non-contact, non-damaged, high-response, and high-sensitivity detection of hydrogen leakage.

Dynamic interferometric measurements of thermally-induced deformations on telescope based on high-strain composite tape-springs

Thin carbon fibre reinforced polymer (CFRP) tape-springs are attractive structures for use in space-based optical instruments because of their compact stowed form, and their high dimensional stability when deployed. In this paper we present, with examples, two inexpensive methods to assess the thermal expansion properties of tape-spring structures: one based on strain gauges to obtain coupon level values, and another based on laser interferometry for structure level measurements. The strain gauge technique is a versatile approach that exploits the thermal output characteristics of the sensors. The thermal expansion characterisation of thin-composite samples measured a longitudinal expansion of 4.44 ppm/∘C and transverse expansion 5.95 of ppm/∘C. The interferometry system is designed with a view to capturing the displacements and tilts that occur when a structure with a low thermal mass, like a tape-spring, experiences a rapid change in flux, as occurs in the space environment. The homodyne interferometer is developed for three degree-of-freedom (DoF) measurements with a resolution of 10−8 m for distances and 10−6 rad for angles. The interferometric setup is based on the classical Michelson architecture and consists of few inexpensive commercial optical components. The source is a 0.8 mW Helium–Neon laser with a wavelength of 632.8 nm. The other elements include two spherical singlets, a right-angle prism, a cubic beamsplitter and a CMOS camera. The recorded interference fringes are analysed by using an algorithm based on Discrete Fourier Transform (DFT). Spectral information on the light intensity signals can be used to determine relative displacements and tilts. The dimensional stability of an optical payload based on high-strain composites was tested. The telescope has a deployable Cassegrain design, which uses six extendable members for the separation of its secondary mirror. Axial deformations between 20–30μm along with angle variations of the order of 0.1 mrad were recorded with good repeatability.

Breakup Mechanism of a Jet in the L-Shape Crossflow of a Gas Turbine Combustor

Experimental investigations are conducted to determine the mechanism and characteristics of a jet in an L-shape crossflow simulating the radial swirl injector of a lean premixed-prevaporized (LPP) combustor. To simplify the radial flow of the actual injector while ignoring the centrifugal effect, the L-shaped 2D-channel is used for the crossflow, and water is used as a fuel simulant. The jet breakup is captured using a high-speed camera, and the density gradient magnitude is post-processed to clarify the spray. The Sauter mean diameter (SMD) of the spray is measured via a laser diffraction method with a helium–neon laser optical system (HELOS). The characteristics of the jet in the L-shape crossflow are compared with the characteristics of the jet in a typical crossflow through the flat channel. The results for different outlet heights of the L-shape channel (H/d0) and different injector positions (L/d0) are presented. A dimensionless number (τ) consisting of a time ratio is introduced to describe the jet characteristics. In a previous work, the spraying tendency was demonstrated for different injector positions. In addition, the effect of the recirculation area on H/d0 was empirically shown. H/d0 determines the size of the recirculation area, and the range of τ determines the jet breakup mechanism inside the L-shape channel. The results of this study present the breakup mechanism of the jet in the L-shape channel flow, which simulates a jet in a radial swirler injector for gas turbine engines. It is expected that these results can be used to assist in designing gas turbine engines with more combustion efficiency.

A single-slit diffraction experiment for measuring laser beam width

A single-slit diffraction experiment in an introductory physics laboratory is generally comprised of a rectangular slit and a laser source. The laser beam is sent to the slit producing the well-known diffraction pattern on the screen. This paper proposes a simple modification of the single-slit diffraction experiment to increase student attention about the laser beam and its diffraction. A single slit can be used to measure laser beam width. The beam width measurement is demonstrated by using a 632.8 nm Helium Neon (HeNe) laser. In this experiment, the laser beam is assumed as a Gaussian beam. The beam width is determined by scanning in one direction across the laser beam. The measurement results are shown to achieve satisfactory results when compared with a commercial laser beam profiler. By measuring the laser beam widths, students will qualitatively observe that the laser beam width increases along propagation distance. This experiment can be an additional exercise in a single-slit diffraction experiment.

The Effects of Low-Level Helium–Neon (He–Ne) Laser Irradiation on Lipids and Fatty Acids, and the Activity of Energetic Metabolism Enzymes and Proteome in the Blastula Stage and Underyearlings of the Atlantic Salmon Salmo salar: A Novel Approach in Salmonid Restoration Procedures in the North

The effect of He–Ne laser irradiation on fishery parameters as well as on biochemical state, including the lipids and fatty acids, the activity of energy metabolism enzymes and the proteome in the blastula stage and in underyearlings of wild Atlantic salmon after irradiation at the cleavage stage/early blastula (considered as the stages when the cell has a high potential for differentiation) was studied. Low mortality rates of eggs were determined during embryogenesis, as well as increased weight gain and lower morality rates of underyearlings in the experimental group. This is confirmed by changes in a number of interrelated indicators of lipid metabolism: a decrease in total lipids content, including diacylglycerols, triacylglycerols, cholesterol esters, and the phospholipids content remained unchanged. The embryos in the blastula stage (experimental group) had higher aerobic capacity and an increase in pentose phosphate pathway activity. The proteome profiles of eggs in the blastula stage were 131 proteins, of which 48 were significantly identified. The major protein was found to be phosvitin. The proteomes of underyearlings were represented by 2018 proteins, of which 49 were unique for the control and 39 for the experimental group. He–Ne laser irradiation had a strong effect on the contents of histone proteins.

Neon laser with wavelengths of 540.1 and 614.3 nm pumped by an inductive pulsed cylindrical discharge

Neon laser with wavelengths of 540.1 and 614.3 nm pumped by an inductive pulsed cylindrical discharge

Comparative Study of Laser- attenuated and Gamma attenuated irradiated larval Vaccines of Dictyocaulus filaria in goats.

A comparative trial between the effect of 3rd stage Dictyocaulus filaria larval vaccine attenuated by continuous emission of visible Helium – Neon Laser of ImW and wave length of ( 632.8 ) nm of (5) minutes exposure that of gamma attenuated larvae at 0.5 k. gray ( Co as radiation Source ) was designed. Each of the two attenuated larval vaccines was given to a group of ( 5 ) kids each . Double immunization doses at ( 35 ) days interval from each vaccine were given orally. The first dose contained ( 1000 ) larvae and the second one ( 2000 ) for each . A challenge dose of ( 100 ) non- irradiated larvae /kg body weight was given after ( 5 ) week to the vaccinated groups and a control non- vaccinated (5 kids ) 3rd group. All animals were slaughtered after 6 weeks post challenge. &#x0D; Results showed that both vaccines revealed 80.7% and 78.1% protection respectively for worm burden as compared to control. Laser attenuated vaccine exhibited a statistically significant inhibition in the fecundity of female worms and larvae secretion in faeces in comparison with the gamma irradiated vaccine.

Inductive Penning plasma neon laser with a wavelength of 585.3 nm

A pulsed inductive Penning plasma laser based on neon with lasing on a wavelength of 585.3 nm was created for the first time. The active medium was pumped by a pulsed inductive cylindrical discharge. Lasing was observed in the afterglow and was obtained only in a mixture of neon with hydrogen. The duration of the optical laser pulses reached 180 ns Full Width at Half Maximum (FWHM) and about 400 ns near the base. The laser beam had a ring form with a diameter of about 42 mm and a width of 2.5 mm. The measured lasing divergence did not exceed 2 mrad.

Effects of Laser Mutagenesis on Microalgae Production and Lipid Accumulation in Two Economically Important Fresh Chlorella Strains under Heterotrophic Conditions

Microalgae produce a variety of high-value products. Enhancing product contents in microalgal cells is one of the efficient ways to decrease production costs. Improved germplasm and heterotrophic cultivation may enhance microalgae biomass and lipid content. In this study, we investigated the effect of three types of laser irradiation and heterotrophic cultivation on lipid productivity, lipid content, and biomass of two Chlorella strains (i.e., FACHB 9 and FACHB 31). Results showed that the highest biomasses of 4.81 g/L (15.03-fold) and 4.66 g/L (7.32-fold) were obtained in the third generation of FACHB 9 and FACHB 31 induced by a neodymium-doped yttrium aluminum garnet (Nd:YAG) laser for 8 min and 12 min, respectively. The highest lipid contents were 525.6 mg/g (1.67-fold) dry weight (DW) and 780.0 mg/g DW (2.20-fold) in the third and the first generations of FACHB 9 and FACHB 31 induced by Nd:YAG for 8 min and by a helium–neon (He–Ne) laser for 4 min, respectively. The highest lipid productivities of 69.82 ± 3.29 mg/L/d (19.7-fold) and 30.71 ± 3.77 mg/L/d (3.1-fold) were obtained in FACHB 9 and FACHB 31 treated by a semiconductor (SC) laser for 4 min and by a He–Ne laser for 12 min, respectively. Our study suggested that laser mutagenesis is a potential method for screening economically important oleaginous microalgae strains.

Determination of Potassium Concentration in Solution Using Optical Fiber Sensors

Potassium is a mineral that has an important role in maintaining fluid balance in the human body and controlling blood pressure in the body. In addition, potassium also plays a role in maintaining the function of the muscles and nerves that control the heart. The development of instruments and methods developed to obtain more accurate measurements of potassium concentration requires an institution with high sensitivity. One of the instruments utilizes the principle of electromagetic wave symptoms made by optical sensor systems with the use of optical fibers for waveguides to maintain their intensity stability. The optical fiber bundle instrument in the optical sensor system to determine potassium concentration in the hope that this instrument can present accurate measurement parameters and better sensor sensitivity. In this study, samples of standard solutions with potassium as a solute and pure water function as solvents. Potassium solution samples that are in the bottom of the vessel there is a flat mirror that reflects the laser beam that has been through the process of absorption by the sample solution. The reflected neon helium laser is transmitted through the optical fiber receiver to measure the change in wave intensity using an optical detector. The intensity of the reflected laser beam waves is read by an optical detector and converted to an electrical energy display by measuring the maximum electrical voltage using a digital voltmeter. The parameters measured in the experiment investigate the relationship between the change in the concentration of the potassium solution and the maximum voltage read on a digital voltmeter. The results of data analysis determine the concentration of potassium to achieve high sensitivity, linearity and accuracy with a sensitivity value of 0.01 mV/ppm, linearity of more than 99%, linear range of 0-10 ppm, so the instrument is very valid and high sensitivity.

Laser Light Treatment of Seeds for Improving the Biomass Photosynthesis, Chemical Composition and Biological Activities of Lemongrass Sprouts

Compared to seeds and mature plants, sprouts are well characterized based on their nutritive values and biological properties. Moreover, laser light application is known to be a promising approach to improving plant growth, photosynthesis, and nutraceutical values. However, no studies have investigated the phytochemicals and biological activity of lemongrass (Cymbopogon proximus (Hochst. ex A.Rich.) Chiov.) sprouts or the further improvement of their quality by applying laser light treatment. We carried out a preliminary experiment for the optimization of laser treatment conditions, finding that a helium neon (He–Ne) laser at 632 nm and 5 mW for 5 min provided the most favorable conditions. We then investigated fresh weight, photosynthetic reactions, and primary and secondary metabolites, including sugars, amino acids, organic acids, essential oils, and phenolic compounds. Moreover, we studied the effect of laser light-induced changes in chemical compositions on the antioxidant, anti-diabetic, and anti-cholesterol activities of Cymbopogon proximus sprouts grown from laser-treated seeds. Laser light treatment increased the photosynthesis and respiration and hence the fresh weight of Cymbopogon proximus sprouts. Overall, sprouting increased most bioactive primary and secondary metabolites as compared to seeds. Increased photosynthesis by laser light improved carbon allocation and raised non-structural carbohydrates, which in turn led to improved synthesis of amino acids, organic acids, and essential oils, as well as phenolic and flavonoid compounds. As a result, laser light significantly improved the antioxidant capacity in terms of increasing the levels of ferric reducing antioxidant power (FRAP) (from 9.5 to 21 µmole trolox/g fresh weight (FW)), oxygen radical absorbance (ORAC) (from 400 to 1100 µmole trolox/100 g FW), and DPPH (from 5% to 25% of inhibation) and enhanced the hypocholesterolemic and antidiabetic activity through increasing the percentage of cholesterol micellar solubility (CMS) inhibition (from 42% to 62%) and glycemic index (from 33 to 17 µmole/g) over sprouts and seeds. In conclusion, the synergism of seed laser treatment and sprouting induced the health-promoting bioactive compounds in Cymbopogon proximus as compared to seeds, which can be applied at a large scale to improve the biochemical, physiological, and nutraceutical values of medicinal and crop sprouts.

Ways to increase the efficiency of fisheries through the use of energy-efficient lighting systems

This article deals with the application of energy-saving electro-technological systems in the rapid development of the fishing industry in the Republic. They provide information on reducing electricity consumption and saving food and feed products through their use. The biological enhancement results of low-intensity laser beams date back to the late 1960s and early 1970s and were derived from the use of a helium neon laser (X = 632,8 nm) and was the first industrially manufactured device. In the optimal regimes of the photovoltaic, hematological parameters were normal. In the absence of light, a clear separation of neutrophilia and leukopenia was observed.