Random Laser

A random laser is a device that has caught a lot of scientific attention because it doesn't need the typical optical cavity that traditional lasers use. Instead, it works by scattering light in a random disordered medium. This multiple scattering acts as the feedback mechanism, allowing the light to travel longer paths through the gain medium, which boosts the process of stimulated emission, necessary for light amplification. Two of the main reasons why researchers are so interested in random lasers are their ease of fabrication and their potential use in sensors. Since they don’t require precise mirrors or cavities, random lasers can be made more simply and at a lower cost. Additionally, their ability to scatter light makes them ideal for detecting small changes in materials, which is useful in sensor technology.

Combining Biomaterial and Polymeric Film

Polymers have been widely used in various works within the field of photonic science, such as the development of new photonic devices. In this context, we used an acrylic resin, which provided good optical quality, as a host matrix for emissive organic dyes, resulting in a flexible solid-state organic dye laser. Random Lasers (RLs) inspired by biomaterials have garnered significant interest in recent years, as random structures can be found in many materials in nature, enabling a wide range of applications across diverse fields.

Eggshell membrane (ESM) is a natural, abundant, and underutilized biomaterial, primarily composed of protein fibers with high flexibility. Made up of layers of collagen fibers with unique optical properties, ESM shows great potential for laser devices. The study reveals that the arrangement of the inner and outer layers of the membrane plays a crucial role in determining the intensity and width of the laser emission. This research holds promise for the development of compact and eco-friendly laser devices that could be used in optical sensors, lighting, and communication systems. Given that ESM is abundant and inexpensive, it offers a sustainable alternative to traditional synthetic materials.

Figure: A simple illustrative diagram of the intricate structure of natural fibers in the ESM. The figure could also include graphs showing the relationship between the ESM configuration and laser efficiency, as well as an example of a flexible polymeric sample produced.

Measuring Milk Fat Content

This study explores new methods for measuring fat content in milk using laser and spectroscopy techniques. It looks at how fat in milk affects light scattering and random laser emission, suggesting a method that could be more efficient and less invasive than traditional analysis methods.

Accurately measuring fat content is crucial in the dairy industry because it affects product quality and compliance with regulations. The proposed method could be used for real-time monitoring of milk quality, improving production efficiency and ensuring customer satisfaction.

Figure: A graph illustrating the correlation between fat concentration in milk and the intensity of emitted light, demonstrating how variations in milk composition can be accurately detected using this method.

The Integration of Cerium Oxide

Studies on new materials, such as CeO₂, are fundamental for optimizing the efficiency of random lasers, including the reduction of the intensity threshold, which is particularly relevant for the development of miniaturized devices and more cost- and energy-efficient systems. The significance of using CeO₂ lies in its ability to provide an essential feedback mechanism for the operation of random lasers, where multiple light scattering processes occur. In the experiment, CeO₂ nanoparticles, in the form of nanorods, reduced the intensity emission threshold and provided a significant narrowing of the linewidth (from 32 nm to 8 nm), marking the transition from spontaneous to stimulated emission.

Another crucial point highlighted is the viability of CeO₂ as an alternative to TiO₂, a material widely used in random laser systems. CeO₂ not only offers comparable optical properties but also exhibits greater chemical stability and resistance to photochemical degradation, making it more suitable for long-term applications in solid-state lasers.

Figure: The graph illustrates the significant decrease in spectral width as a function of increasing pump energy, and it also includes a detailed view of two spectra where the difference in spectral width at two distinct pump energies can be observed.