Journal of Lasers, Optics & Photonics

Optical limiting is a nonlinear optical process where the transmission of light decreases with increasing light intensity, protecting sensitive optical devices and human eyes from damage by intense light sources such as lasers. Materials exhibiting optical limiting are of significant interest for applications in optical limiters and sensors. One promising class of materials for this purpose is semiconductor nanocrystals embedded in polymer matrices, particularly Cadmium Selenide (CdSe)-based multiphase polymer nanocomposite films. CdSe nanocrystals are semiconductor quantum dots that have attracted extensive research due to their unique optical properties, including size-tunable bandgaps, high photoluminescence quantum yields, and nonlinear optical responses. These properties arise from the quantum confinement effect, where the electronic and optical properties of the nanocrystals are controlled by their size and shape. CdSe nanocrystals can be synthesized using various methods, such as colloidal synthesis, which allows for precise control over their size and surface chemistry.

Copper is an essential material in various industrial applications due to its excellent electrical and thermal conductivity. Pure copper foils are particularly significant in electronics, where they are used for circuit boards, connectors, and heat sinks. However, welding copper foils poses significant challenges due to copper’s high reflectivity and thermal conductivity. Traditional welding techniques often struggle with copper, leading to defects and suboptimal joints. The advent of blue diode lasers has introduced a promising method for welding copper due to their ability to overcome these challenges. This paper explores the mechanical properties and weldability of pure copper foils welded using a blue diode laser, focusing on the unique advantages and potential limitations of this method.

The advancement in material science has brought about the development of novel materials with enhanced properties to meet the growing demands of various industries. One such innovation is the creation of composites, which combine two or more distinct materials to produce a new material with improved characteristics. Among these, carbon-filled Polyvinyl Alcohol (PVA) composites have garnered significant attention due to their unique properties and versatile applications. A promising technique to fabricate these composites is Laser Ablation in Liquids (LAL), which offers precise control over particle size and distribution.

Toys of different brands were analyzed by Laser Induced Breakdown Spectroscopy (LIBS) technique employed for the analysis of toxic and nontoxic elements. All samples were irradiated without sample preparation treated under the ambient environment of argon gas. The analysis of emitted spectra reveals the presence of different elements in the samples which was verified by the National Institute of Standard and Technology (NIST) database. Both toxic and non-toxic elements like lead, tin, mercury, potassium and magnesium are found indifferent concentrations. The concentration of heavy metals like lead, mercury and tin in different toys were in the range of 897.2 ppm-320.5 ppm, 88.2 ppm-140.4 ppm and 8.4 ppm-10.2 ppm respectively which is much higher than the permissible value set by US Environmental Protection Agency (US EPA), US Food and Drug Administration (US FDA) and other regulatory authorities. The concentration of non-toxic elements like magnesium and potassium are within safe permissible limits.