Iraqi Journal of Laser

This work examines the beam squint effects of quantum-based carbon nanotube (CNT) antenna arrays for optical plasmonic communication systems functioning within the 300 THz to 700 THz frequency spectrum. The distinctive quantum confinement characteristics of carbon nanotubes (CNTs), together with surface plasmon polariton (SPP) interactions, result in notable frequency-dependent phase shifts, causing beam squint errors in phased array systems. Simulation findings indicate that at 300 THz, a CNT array with an inter-element spacing of λ/2 (500 nm) has a beam squint of 0.2° per 100 THz bandwidth. As the frequency ascends to 700 THz, the beam squint effect amplifies, reaching 0.8° per 100 THz as a result of heightened plasmonic dispersion and quantum-induced phase shifts. The group delay variation throughout the bandwidth is measured at 12.4 fs at 300 THz and 5.6 fs at 700 THz, affirming the nonlinear characteristics of quantum plasmonic wave propagation. The results underscore the significant influence of beam squint in nanoscale optical phased arrays and provide a basis for the creation of adjustable CNT-based plasmonic antennas for advanced optical communication systems.

In this study, laser-induced breakdown spectroscopy (LIBS) was used to analyze the plasma generated from a Zn:Cu alloy (x = 0.9) using a Nd:YAG laser at 1064 nm. Plasma was generated at different laser pulse energies ranging from 400 to 800 mJ. The electron temperature (Te) was determined using the Boltzmann plot method, while the electron number density (ne) was calculated using Stark broadening. Other plasma parameters were also evaluated, including plasma frequency (fp), Debye length (λD), and Debye number (Nd). The results showed that Te increased from 0.846 eV at 400 mJ to 0.906 eV at 800 mJ, and ne increased from 1.000 × 10¹⁸ cm⁻³ to 1.121 × 10¹⁸ cm⁻³. Plasma frequency increased from 898.000 × 1010 Hz to 950,868 × 1010 Hz, while the Debye length slightly decreased from 0.683 × 10⁻5 cm to 0.668 × 10⁻5 cm. The Debye number showed modest variation around 1300, reflecting relatively stable collective behavior across the energy range. These findings indicate that higher laser energy leads to hotter and denser plasma, enhancing the emission intensity and plasma characteristics. The study contributes quantitative insights into Zn–Cu plasma behavior under varying laser energies, providing potential applications in material diagnostics using LIBS.

Objectives: This study aims to detect the penetration of the AH Plus sealer in the coronal third using a pulsed (Er, Cr: YSGG) laser with a short pulse duration when the SWEEPS was used to activate irrigation (Shock wave Enhanced Emission Photoacoustic Streaming). Methods: A total of 28 single-rooted mandibular premolars. The laser used is pulsed Er, Cr: YSGG assisted by the SWEEPS technique. There are four groups of samples (n = 7) for each: Group 1: Traditional syringe irrigation using 5 mL of 17% EDTA. Group 2: passive ultrasonic irrigation using mL of 17% EDTA. Group 3: Er, Cr: YSGG laser-induced SWEEPS using 5 mL of 17% EDTA. Group 4: Er, Cr: YSGG laser-induced SWEEPS using 5 mL of 5.25% NaOCl and 5mL of 17% EDTA. The laser parameters were selected according to the pilot study (Air and water 1%, 0.75 W, 5 Hz, and a short pulse duration of 60μs). The irradiated teeth were obturated by AH plus sealer mixed with Rhodamine B, and the weight percentage was 0.001. Horizontal sectioning was performed at 9mm lengths away from the apex. Four different sites (lingual, distal, mesial, and buccal) were used to determine the depth of sealer penetration. A confocal laser scanning microscope was used to detect the deepest penetration of the sealer. Statistical analysis was conducted using Dunnett t-tests with a significant level set at p≤0.05. Results: The obtained results revealed that AH plus sealer reached the wall of canals in four positions (lingual, distal, mesial, and buccal) at G4 in comparison to G3 and G2 for the selected laser parameters (Air and water 1%, 0.75 W, 5 Hz, and a short pulse duration of 60μs). The data are summarized as follows (mean ± standard deviation in μm) in G1 is 206.20±16, G2 is 593.02±131.67, G3 is 818.58±97.99, G4 is 986.94±27.9 for the lingual side. Conclusion: it is concluded that the pulse duration(60μs) of Er, Cr: YSGG laser was authorized successfully upon irrigation activation to achieve the deepest point in the root canal for four positions (lingual, distal, mesial, and buccal), so the lingual side was the best values of the sealer penetration. The best parameters are used in G4. These results suggest that the use of Er, Cr: YSGG laser with SWEEPS technique enhance the penetration of endodontic sealers into dentinal tubules thereby improving the seal quality.

Background: This vitro study investigated the effectiveness of Er,Cr:YSGG laser-activated irrigation in removing root canal filling remnants during endodontic retreatment. The technique used photon-induced photoacoustic streaming (PIPS) at 700 µs pulse duration to activate 2.5% sodium hypochlorite (NaOCl) and 17% EDTA. Materials and methods: Twenty-one extracted human maxillary and mandibular premolars with single roots were instrumented and obturated using gutta-percha and a bioceramic root canal sealer. After retreatment using nickel-titanium rotary files (XP-endo Retreatment), the specimens were randomly assigned into three groups (n=7 per group) according to the irrigation technique: Group 1: conventional syringe irrigation (control), Group 2: passive ultrasonic irrigation, Group 3: laser-activated irrigation using Er, Cr:YSGG laser (2780 nm, 700 µs pulse duration, 5 Hz, 1 W, RFT2 tip, with no air or water spray). All samples were sectioned longitudinally and examined under a scanning electron microscope (SEM) to assess the presence of residual filling materials in the coronal, middle, and apical thirds. Cleanliness scores were assigned by two calibrated endodontists based on a 4-grade scoring system and were statistically analyzed using one-way ANOVA followed by Tukey’s post hoc test. The significance level was set at α = 0.05. Statistical analysis revealed a significant difference among the groups (P < 0.05). Group 3 showed significantly lower residual debris compared to Groups 1 and 2 across all root thirds, while the difference between Groups 1 and 2 was not statistically significant (P > 0.05).
Results: Group 3 (n = 7) exhibited significantly lower residual debris compared to Groups 1 and 2 across all canal thirds (P < 0.05). The mean cleanliness scores were highest in the coronal third, followed by the middle and apical thirds. No statistically significant differences were observed between Group 1 and Group 2 (P > 0.05), suggesting limited effectiveness of ultrasonic irrigation compared to laser activation.
Conclusion: The use of Er,Cr:YSGG laser-activated irrigation with PIPS at a 700 µs pulse duration, combined with 2.5% NaOCl and 17% EDTA, significantly improved the removal of root canal filling remnants during retreatment. These findings suggest that laser-activated irrigation may serve as an effective adjunct to conventional retreatment protocols, offering enhanced cleaning efficacy across all canal levels.

This study aims to evaluate the feasibility of using pulsed Nd:YAG laser spot welding to join dissimilar metals consisting of nickel and nickel-plated copper in busbar joints for lithium-ion batteries. The effects of key operating parameters, namely laser energy, pulse repetition rate, and focal position, on the mechanical and structural properties of the weld were examined. The results showed that an energy of 13 joules achieved the highest peak shear force of approximately 273 N with a homogeneous melt zone and limited surface defects, while an energy of 10 joules recorded the highest hardness value (370HV0.300) due to the balance between energy input and cooling rate. It was also found that a repetition rate of 20 Hz and a focal position at 0 mm represent the optimal conditions for obtaining stable mechanical and microstructural properties. Although the results confirm the possibility of obtaining high-quality welds using this technique, full reliability verification requires further analysis through scanning electron microscopy (SEM), phase analysis (EDS/XRD), and fracture pattern studies to determine failure locations. The study also recommends conducting additional experiments to assess long-term performance under various operating conditions such as vibration, temperature fluctuations, and humidity. Thus, this work contributes a scientific basis that can be relied upon to develop more reliable manufacturing processes in modern battery applications.

Introduction: A mucocele is a noncancerous abnormality of the mouth that develops when small salivary gland ducts become clogged or when the mouth is traumatized. Due to its many benefits, including less postoperative pain and bleeding and faster recovery, diode laser therapy has grown in popularity. In this particular instance, a 980 nm diode laser was used during a surgical procedure to remove a mucocele from the lower lip.
Case Presentation: The patient was a 23-year-old guy who complained of occasional, painless swelling of the lower lip. Officially, a mucocele was determined. Under local anesthetic, the lesion was removed using a 980 nm diode laser. This procedure allowed for the exact excision of tissue with little damage to adjacent structures. The patient experienced no major side effects or discomfort after the treatment, which indicates that it was well-tolerated. There were no indications of impaired healing during the following appointment.
Conclusion: This case study proves that the 980 nm diode laser is more effective than conventional surgical methods for treating mucoceles. Quick healing, less discomfort, and no incisions are all benefits of the diode laser. It provides a new option for treating oral mucoceles that has shown remarkable improvements in patient outcomes.

The hole transport layers are critical components of organic conductor-based devices. The metal nanoparticles (NPs) are excellent materials for this purpose. This paper describes the preparation of silver nanoparticles (Ag NPs) using a laser method, which were then mixed with the organic polymer poly(3-hexylthiophene) (P3HT) at different concentrations (0.1, 0.3, and 0.4 wt%). The structural morphology, structure, and optical properties of the new nanocomposite were examined using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), and UV-Vis spectroscopy. The XRD data showed that the created Ag NPs have a crystal structure, with the strongest peaks seen at angles of 38.1°, 44.3°, 64.4°, and 77.4°. The FESEM and AFM tests showed that having more Ag NPs makes the surface rougher and helps spread the nanoparticles better, where the surface roughness increased from 2.04 to 2.46 nm, the mean roughness of the film (Ra) changed from 1.55 to 1.81 nm, and the maximum height of the film (Rmax) ranged from 22.34 to 25.38 nm. The UV-Vis spectroscopy results showed that the material absorbed lighter due to the localized surface plasmon resonance (LSPR) effect, which caused the absorption peaks to move to shorter wavelengths and lowered the optical energy gap from 2.1 eV for pure P3HT to 2 eV with a 0.3 wt% concentration of AgNPs. P3HT nanocomposites with Ag nanoparticles have better structure and optical properties, which make them ideal for organic solar cells and other electronic applications.

Laser diode with 980 nm has many attractive applications in telecommunication and photonic systems especially when it used for pumping the Erbium–Doped Fiber Amplifiers (EDFAs) which is an essential c- band amplifier that used in many applications for enhancing the nonlinear system conversion efficiency. In this work pulsed laser diode was manufactured after electronically implement the divider circuit with thermal stability of 14 pin 980 nm butterfly laser diode (AGREE SL 90S31A) that has maximum power of 160 mW. This driver circuit was based on the LM317 adjustable current regulator. The electronically chopped 980 nm laser diode achieved stable modulation in the frequency range from 1 Hz to 1 kHz. The proposed driver circuit is simple, low-cost, and successfully provides the required optical modulation for tapered fiber interferometer applications, making it a practical alternative to expensive electro-optic modulation systems such as commercial Lithium Niobate electro-optic modulators which are costly and also require expensive drivers to operate.

The Er, Cr: YSGG laser has emerged as a promising tool for safe and precise bone ablation in dental and maxillofacial procedures. This ex vivo study aimed to optimize the laser parameters to achieve efficient bone cutting with minimal thermal side effects.
Method: This ex vivo study aimed to evaluate the histological effects of varying ER, Cr: YSGG laser parameters on bone incision quality. Mandibular bone samples were collected from three freshly slaughtered sheep and sectioned into six blocks. Osteotomies were performed using an ER, Cr: YSGG laser (2780 nm, Waterlase iPlus) at six different power-frequency combinations (2.5W/20Hz, 4W/20Hz, 6W/20Hz, 4W/30Hz, 6W/30Hz, and 8W/30Hz). Each specimen was irradiated in contact mode for 25 seconds using a MGG6-6 tip, and incisions were evaluated histologically after fixation, decalcification, and H&E staining. Measured variables included incision length, width, length-to-width ratio, carbonization, and precision.
Results: ER, CR: YSGG lasers can be considered practical, effective, and easy for bon incisions. There is no thermal damage. The quality of laser incision at 4W, 20Hz is the best among the parameters(p=0.013).