Cw Laser Beam Research Articles

Optical nonlinear properties of a new polyamide from crystal violet terephthalate

In this study, the nonlinear optical properties of a new polymer poly crystal violet terephthalate (PCVT) as a solution and a thin film with different concentrations of 0.2, 0.6, and 1 mM and input power were investigated by using Z-scan technique at 532 nm CW laser beam wavelength. The negative nonlinear refractive index n 2 as well as reverse saturable and saturable absorption β of the solution and film PCVT samples were determined. Figures of merit were also determined. In comparison with the Z-scan results, a self-diffraction pattern setup was used to measure nonlinear refractive index. Results showed a significant laser power dependence of the number of far-field diffraction rings with power and concentration, consistent with the Z-scan data. The PCVT sample exhibited good optical limiting behavior. Hence, PCVT has important nonlinear properties, and its figures of merit can be optimized by adjusting the PCVT concentration and input power. PCVT is a promising candidate for the design of optical photonic switching and optical limiter devices.

Fully quantum-kinetic theory of the steady-state cooperative photoluminescence from two near-identical emitters

We have developed a theory of cooperative photoluminescence from two closely spaced particles using the density matrix method. The theory provides simulations of the photoluminescence excitation and emission spectra by nonidentical quantum emitters entangled by the dipole–dipole interaction in presence of a cw laser beam. The excitation spectra are shown to be consistent with all known experiments to date with pairs of coherently coupled organic molecules in thin solid layers. The simulations were performed with the use of the Bogoliubov–Born–Green–Kirkwood–Yvon (BBGKY) hierarchies for reduced density matrices and correlation operators of the quantum emitters and photonic subsystems. This method gives a straightforward way to describe the dipole–dipole coupling and entanglement of the emitters. We have also calculated the emission spectra to demonstrate the expected spectral patterns.

Synthesis of a new cyclic amide derivative: Study its optical nonlinear properties and molecular docking

2-(1,3-dioxoisoindolin-2-yl)-N-(pyrimidin-2-yl) acetamide is synthesized as a new cyclic amide derivative. The structure of this derivative has been characterized by NMR, FTIR, and Mass spectra. The molecular docking calculations of the prepared cyclic amide against (PDB ID: 3PP0) receptor are performed. The prepared compound has the potential to inhibit breast cancer cells, according to molecular docking results. The DFT/B3LYP via 6–311 G(d,p) level was performed to optimize the geometrical structure and the global and local reactivity descriptors of this compound. The calculated values of polarizability and hyperpolarizability of the prepared cyclic amide equal 30.774 ×10−24 esu and 114.678 ×10−32 esu, respectively. The nonlinear optical (NLO) properties of the prepared compound are studied under irradiation with a visible, cw laser beam. The nonlinear refraction index (NLRI), n2, of the compound is estimated using diffraction patterns (DPs) and the Z-scan techniques, where as high as 2.682 ×10−11 m2/W are obtained. The optical limiting property of the prepared compound is studied using the same laser beam. An optical limiting threshold of 15 mW is obtained.

Synthesis of a New Schiff Base: Nonlinear Optical Properties Investigations.

A Schiff base is prepared by the reaction of 7-hydroxy-1-naphthaldehyde with 4-aminoben-zenesulfonamide. The prepared Schiff base L4 compound was characterized by 1H NMR, Mass and FTIR spectroscopies. The optimization of the prepared L4 compound is carried out via DFT-B3LYP and 6-311G (d,p). The nonlinear optical (NLO) properties of the prepared L4 compound are investigated theoretically by the calculation of some quantum chemical descriptors (QCDs). TD-DFT via B3LYP and 6-311G calculations are used to study L4 compound UV-vis. spectrum at the same theoretical method and level. The L4 compound NLO properties are examined via irradiation with a CW laser beam, where the nonlinear index of refraction (NLIR) is calculated via diffraction patterns (DPs) and the Z-scan and as high as 4.579 × 10-11 m2/W of NLRI is obtained. Static (S) and dynamic (D) all optical switching (AOS) are examined using two CW and pulsed laser beams of wavelengths (473 and 532) nm.

Synthesis, characterization and nonlinear optical properties of new azo compound using CW laser beam

Synthesis, characterization and nonlinear optical properties of new azo compound using CW laser beam

Thermal lens investigation of the CdSe quantum dots using dual beam z-scan technique

We highlighted on the thermal lens (TL) effect of Cadmium Selenide quantum dots (CdSe QDs) using dual beam z-scan technique. The thermal lens nonlinear optical properties of CdSe QDs were investigated by applying the two CW laser beams (λ = 532 nm and λ = 632.8 nm). The thermal lens parameters of the CdSe solutions, such as: the on-axis phase shift (θ), the thermal diffusivity (D), and thermal diffusion time (tc) were extracted using the theoretical thermal lens model. Our results give new insight into the CdSe QDs dissolved in toluene and are valuable for further development of semiconductor QDs optical devices.

Observing Variation in Whispering Gallery Mode Resonance of a Trapped and Levitated Dye Doped Microdrop.

Whispering gallery mode (WGM) resonance was created in a spherical micro drop. A gradual shift in the resonance were observed. For a 600 nm droplet radius, the blue shift were 1.5, 0.7, 3.7 nm. It was estimated that such a shift corresponds to a reduction in optical radius of the droplet by 1.3, 0.6, 3.3 nm respectively. The droplet was created from a solution of glycerol, methanol and rhodamine 6G dye, and was trapped and levitated in a modified Paul trap. The WGMs were created by optically exciting the dye material from an external 532 nm cw laser beam. A shift in the WGM was observed during a gradual increase in power of the excitation laser, and a reason for such a shift was thought to be thermal evaporation of the liquid. For a larger droplet an initial 0.1 nm thermal expansion was also estimated, preceding the volume contraction. Such an expansion was negligible for a smaller droplet. The rate of change of the blue shift depends upon initial radius of the droplet. For the smaller droplet the estimated rate of change of WGM with a change in optical radius, was 0.771. For larger droplet, this rate is lower.

Curcumin analogue: Synthesis, DFT and nonlinear optical studies

The synthesis of a new curcumin analogue dye via 3-chloro-2,4-pentanedion condensing with an aromatic aldehyde is considered. Following that, the synthesized compound is diagnosed utilizing spectroscopic methods, including FTIR, mass, 1H NMR, and 13CNMR. The curcumin analogue geometric optimization and theoretical studies are conducted on thermodynamic properties using DFT. The B3LYP techniques, which are hybrid functional with a 6–311+G(d) as the basis set, are adopted to compute the HOMO, LUMO, and Mullikan atom charges of the studied compound. The curcumin analogue dye nonlinear optical (NLO) properties are examined under excitation with a 473 nm, low power, cw and TEM00 mode laser beam. The index of nonlinear refraction (INLR) and coefficient of nonlinear absorption (CNLA) are estimated using diffraction patterns for the former and Z-scan for the latter. The INLR reaches a value as high as 6.86×10−11 m2/W, while the CNLA reaches 2.23×10−3 cm/W. All-optical switching (AOS) is tested in the novel curcumin analogue dye using two methods: static AOS and dynamic AOS.

Sonochemical‐Promoted Multicomponent Synthesis of a New Amidoalkyl Naphthol Derivative Catalyzed by [(Msim)Cl] Ionic Liquid and Assessment of Its Nonlinear Optical Properties

AbstractThe sonochemical‐assisted multicomponent reaction catalyzed by ionic liquid, solvent‐free synthesis, improving chemical structure, computational calculations, and nonlinear optical properties (NLO) assessment of a new amidoalkyl naphthol derivative 4, that is, [N‐((2‐hydroxynaphthalen‐1‐yl)(4‐nitrophenyl)methyl)‐2‐phenylhydrazinecarbothioamide (C24H20N4O3S), are introduced. The corrected structure of the synthesized derivative 4 is confirmed by different spectroscopic techniques viz., (1H and 13C) NMR, Infrared radiation (IR), Mass spectra, and UV‐vis. spectra. To obtain geometrical structure and confirm the experimental findings, DFT‐assisted B3LYP/6‐31G* method is used. The NLO properties of the synthesized derivative are studied using two visible laser beams where its nonlinear refraction index (NLRI) at 473 nm cw laser beam is obtained using diffraction patterns (DPs) and the Z‐scan techniques. As high as 5.312×10−11 m2/W of NLRI is obtained. The all‐optical switching (AOS) which is usually carried out utilizing two laser beams, the controlling and controlled, is generalized by the use of three laser beams, controlling, 473 nm beam and two controlled 532 nm and 635 nm beams.

Continuous wave cavity ringdown spectroscopy incorporating with an off-axis arrangement, white noise perturbation, and optical re-injection

We present an ultra-sensitive continuous wave cavity ringdown spectroscopy (cw-CRDS) spectrometer to record high resolution spectra of reactive radicals and ions in a pulsed supersonic plasma. The spectrometer employs a home-made external cavity diode laser as the tunable light source, with its wavelength modulated by radio-frequency white noise. The ringdown cavity with a finesse of ∼105 is arranged with an off-axis alignment. The combination of the off-axis cavity and the white-noise perturbed laser yields quasi-continuum laser-cavity coupling without the need of mode matching. The cavity is further incorporated with an extra multi-pass cavity for optical re-injection of light reflected off the master cavity, which significantly increases the throughput power of the high-finesse cavity. A fast switchable semiconductor optical amplifier is used to modulate the cw laser beam to square wave pulses and to initialize timing controlled ringdown events, which are synchronized to the plasma pulses with an accuracy of ∼3 µs. The performance and potential of the cw-CRDS spectrometer are illustrated and discussed, based on the high resolution near-infrared spectroscopic detection of trace 13C13C radicals generated in a pulsed supersonic C2H2/Ar plasma with a pulse duration of ∼50 µs.

Synthesis and investigation of nonlinear optical properties of Azo-SR8 compound using visible laser beams

The main objective of this study is to explore the properties of a chemical compound called Azo-SR8, with a focus on its synthesis, characterization, and nonlinear optical (NLO) properties. To achieve this, several methods are utilized, including 1H and 13C NMR, mass and absorption spectra, differential scanning calorimetry (DSC) thermogram, optimized structure, and investigation of frontier molecular orbitals. NLO properties of Azo-SR8 are analyzed by subjecting it to a cw 473 nm laser beam and using diffraction patterns (DPs) and Z-scan techniques to estimate the nonlinear index of refraction (NLIR) value. The compound's all-optical switching (AOS) capability is investigated using static and dynamics techniques with two cw laser beams. The obtained results provide valuable information on the potential uses of Azo-SR8 in the field of optics.

Effect of sample position on formation of spatial-self phase modulation ring patterns in poly(azaneylylidene-acylene)

Poly(azaneylylidene-acylene) "DAZA" polymer has been synthesized and characterized using different spectroscopic techniques. Self-diffraction ring patterns at far field were observed, when the DAZA polymer was irradiated with a CW laser beam. The influence of sample position, geometrical pumping and laser power has been investigated on the formation of the far field self-diffraction ring patterns of the Gaussian laser beam passing through the DAZA polymer as nonlinear medium. Then, the Fresnel-Kirchhoff diffraction formula was applied to perform simulation of the self-diffraction ring patterns with different laser power at two sample positions before and after the focal point (z = 0) with respect to the geometrical pumping. Our results have shown the effect of type of geometrically pumping on the sample cell (horizontally /vertically) with respect to the distortion of the SSPM patterns. It has been found that, good consistent agreements between experimental and theoretical patterns.

Thermal nonlinearity and all-optical switching of synthesized Azo-Cl compound

Azo-Cl compound is synthesized and fully characterized via NMR and mass spectroscopies. The Azo-Cl compound thermal properties, theoretical chemical shifts, chemical structure, electron absorption spectrum, frontier molecular orbitals, the atomic dipole moment, corrected Hirshfeld charge analysis and electrostatic molecular potential of the Azo-Cl compound are studied in details. The Azo-Cl compound nonlinear refractive index (NLRI) is estimated via diffraction patterns (DPs) and the Z-scan, using low power continuous wave (cw) laser beam. The all-optical switching (AOS) property is recognized in the Azo-Cl compound using two laser beams. We found that the value of the NLRI of sample calculated by the diffraction patterns is greater than the value calculated by the Z-scan, due to the use of different input powers in both cases. The experimental results proved that the sample showed a high NLRI in the range of 10−7 calculated by the Z-scan method under low input power of 5 mW, which indicates that the Azo-Cl compound is a good candidate to be used in optical device applications.

Synthesis, band gap structure and third order non-linear optical properties of zinc tungsten oxide nanocomposite using a single CW laser beam.

In this study, a composite of zinc tungsten oxide nanoparticles (W-ZnO NPs) has been synthesized via mixing Na2WO4 and zinc acetate in water, followed by dropwise addition of NaOH. The synthesized W-ZnO NPs were characterized using measurement methods such as XRD, dynamic light scattering (DLS), Scanning electron microscopy (SEM) and UV-Vis. Also, the results were compared with the pure synthesized ZnO and WO3 NPs. Non-linear optical properties of the synthesized composite were measured using the Z-scan technique with a continuous wave Nd-Yag laser. The negative non-linear absorption coefficient of the components was obtained which indicates that the saturation absorption occurred in this composite. In comparison with pure ZnO NPs, non-linear absorption decreases which can be attributed to the negligible optical response of WO3 structures. Also, the negative value of the close aperture Z-scan curve shows that the thermal lensing effect is the main reason for the third-order non-linear refraction.

The substituent effect on CW laser beam self-action manifestation under UV irradiation of azo-azomethine PMMA composites thin films

We report synthesis and study of E→Z→E photoswitching transformations of methyl-substituted azo-aldehyde and six novel corresponding azo-azomethines containing electron withdrawing/donating substituents in para-position to – CHN– bond, being analyzed by UV–Vis and 1H NMR spectroscopy techniques. Impact of donor/acceptor substituent nature on isomerization kinetics was studied in THF solutions by light activation at 390 nm. We obtained high optical quality of PMMA thin films doped with mentioned dyes. It was characterized with both angularly resolved optical elastic scattering data and nonlinear refractive/absorptive optical responses analysis via CW laser beam self-action effects manifestation at wavelength 532 nm. Pronounced self-focusing effect contribution was shown for electron donating substituents (-CH3, -OCH3) and self-defocusing one for electron withdrawing -NO2 group. UV irradiation at 254 nm provides switching from self-defocusing to self-focusing mode of -NO2 substituted dye-doped film with refractive nonlinear optical response efficiency Re(χ(3)) ≈10−2 esu on background of moderate photoinduced absorption effects manifestation.

DFT structural and optical nonlinear investigations of a synthesized new azo β-diketone dye

A new azo β-diketone (NA1) compound is synthesized by coupling reaction of 4-aminoantipyrine with acetylacetone. The NA1 compound is characterized via FTIR, Mass, 1H NMR and 13C NMR spectroscopies. The keto-enol tautomers of the compound electronic structures and energies are investigated using density functional theory (DFT) via B3LYP method/6-311G (d,p) level. The NA1 compound nonlinear optical (NLO) properties are studied via the diffraction patterns (DPs) and the Z-scan where the compound nonlinear index of refraction (NIR), the optical limiting (OLg) property using 473 nm visible, low power, continuous (cw) laser beam are used while the all-optical switching (AOS) property is studied using two laser beams of wavelengths 473 nm and 532 nm.

Generation of multiple obstruction-free channels for free space optical communication.

Multi-filament structures produced by vortical high-power femtosecond pulses propagating through clouds and fog can simultaneously clear two channels with cylindrical and annular profile. We present a method to achieve Free Space Optical (FSO) communications through such highly scattering media by propagating appropriately shaped laser modes through these channels. As a proof of concept, we implemented a Laguerre-Gaussian beam as information signal carrier to demonstrate transmission of 543-nm CW laser beam through a 1-m long cloud chamber using both channels. The low power of the information signal in this experiment allows considering applications in Earth-satellite FSO communication.

Semi-natural simulation of the angular matching of the axes of the working and marker laser beams in a high-precision laser ranging system

This paper describes an automatic adjustment system designed to measure and automatically minimize the difference in angular mismatch between the optical axes of a working (probe) beam and a marker beam that simulates the optical axis of the detector channel in a laser ranging system. This paper is primarily focused on the specifications of the basic components of the measurement system (laser sources, controllable optomechanical components, and sensors used to measure the angular orientation of the laser beams) used to maintain precision angular matching of the working and marker laser beams in order to develop a process for semi-natural simulation of a precision laser ranging system to produce and study angular matching between the working and marker beam axes. This semi-natural simulation was used to model angular matching of the working and marker laser beams in a high-precision laser ranging system; the simulation was implemented using a laser system specifically developed for the purpose. The main results include a novel laser facility developed for semi-natural simulation of the angular matching of the probe (1064 nm) and marker (671 nm) beams in a laser ranging system where this difference in matching does not exceed 1″. The facility periodically relays images of the laser beams to a polarization-based unit for matching of the beams using spatial filters. The facility was used to obtain experimental data on the positional characteristics of a quadrant photodiode and CMOS-array digital camera used as a laser beam matching unit. We show that this type of digital camera is preferred since it does not require advance knowledge of the positional characteristic. Initially aligned laser beams were observed to randomly become misaligned due to angular instability in the laser beams. We have shown that the angular matching of the pulsed probe and CW marker beams can be automatically controlled using a motorized mirror installed outside the marker-beam optical system and also propose an algorithm for operation of the marker beam in this mode. The scientific value of this paper is based on the novel nature of the laser sensor facility, the experimentally measured characteristics of the hardware components used in the marker laser channel, and the fact that the matching of the pulsed and CW laser beams can be controlled by means of motorized mirrors. The paper has practical value in that a procedure has been developed for semi-natural simulation of the angular matching of probe and marker beams to support the design of high-precision laser ranging systems operating in the near-infrared spectrum.

Synthesis, optical nonlinear properties, and all‐optical switching of curcumin analogues

AbstractThe curcumin analogues (Cur‐MeS and Cur‐MeO) are synthesized using the 3‐chloroacetyl acetone and aromatic aldehydes reaction. Both compounds are characterized using FTIR, LC‐MS, 1H NMR, and 13C NMR spectroscopies. The geometric optimization and thermodynamic properties of the two compounds are carried out theoretically using DFT. The highest HOMO, lowest LUMO, and Mullikan atom charges of the two compounds are calculated using the B3LYP and CAM‐B3LYP methods which are hybrid functionals with a 6‐311+G(2d,p) as the basis set. The nonlinear optical (NLO) properties of both compounds are studied using the spatial self‐phase modulation (SSPM) through the diffraction ring patterns (DRPs) and the Z‐scan techniques, using a continuous wave (cw) low power 473 nm laser beam. The index of nonlinear refraction (INR) of both compounds is calculated by the two techniques. The all‐optical switching property of both samples is tested using two visible cw laser beams.

Proximity-effect-related reduction of the minimum element size in thermochemical laser writing

This study is intended to identify patterns in reducing the minimum size of writable elements in a structure as a function of the distance between elements when they are produced successively by direct thermochemical recording on a thin metal film using direct laser thermochemical writing, as a result of natural thermo-optical effects. Subject of study. The change in writable-element size (the proximity effect) studied here occurs because reduced absorption at the periphery of the beam as it passes through films on which elements have previously been written results in containment of the energy. Methods. This effect was studied by obtaining a solution to the quasi-steady-state heat conduction equation in closed form while taking into account the time-dependent, nonuniform spatial distribution of optical properties within the sample, using titanium films oxidized by exposure to laser light in air as an example. The model results are compared against available experimental studies of the optical and geometric properties of structures written on a 10 nm titanium film by a focused near-infrared cw laser beam. Main results. This research led to a means of predicting the widths of successively written tracks as a function of track separation. The upper threshold track separation values where the effect begins and the lower threshold values below which the new track no longer appears were determined. Both the theoretical and experimental results reveal that the resolution of thermochemical laser writing on thin metal films that form optically transparent oxides can be increased. Practical significance. The theoretical model proposed in this paper can be used to determine the laser exposure parameters required to produce various high-resolution photonic components, such as diffractive optical elements, half-tone photomasks, etc.