An ultraviolet (UV) light induced fluorescence study to discriminate fake tequila from genuine ones is presented. A portable homemade system based on four light emitting diodes (LEDs) from 255 to 405 nm and a miniature spectrometer was used. It has been shown that unlike fake and silver tequila, which produce weak fluorescence signal, genuine mixed, rested, and aged tequilas show high fluorescence emission in the range from 400 to 750 nm. The fluorescence intensity grows with aging in 100% agave tequila. Such fluorescence differences can even be observed with naked eyes. The presented results demonstrate that the fluorescence measurement could be a good method to detect counterfeit tequila.

Achieving accurate measurements of inflammation levels in tissues or thickness changes in biological membranes (e.g., amniotic sac, parietal pleura) and thin biological walls (e.g., blood vessels) from outside the human body, is a promising research line in the medical area. It would provide a technical basis to study the options for early diagnosis of some serious diseases such as hypertension, atherosclerosis or tuberculosis. Nevertheless, achieving the aim of non-invasive measurement of those scarcely-accessible parameters on patient internal tissues, currently presents many difficulties. The use of high-frequency ultrasonic transducer systems appears to offer a possible solution. Previous studies using conventional ultrasonic imaging have shown this, but the spatial resolution was not sufficient so as to permit a thickness evaluation with clinical significance, which requires an accuracy of a few microns. In this paper a broadband ultrasonic technique, that was recently developed by the authors to address other non-invasive medical detection problems (by integrating a piezoelectric transducer into a spectral measuring system), is extended to our new objective; the aim is its application to the thickness measurement of sub-millimeter membranes or layers made of materials similar to some biological tissues (phantoms). The modeling and design rules of such a transducer system are described, and various methods of estimating overtones location in the power spectral density (PSD) are quantitatively assessed with transducer signals acquired using piezoelectric systems and also generated from a multi-echo model. Their effects on the potential resolution of the proposed thickness measuring tool, and their capability to provide accuracies around the micron are studied in detail. Comparisons are made with typical tools for extracting spatial parameters in laminar samples from echo-waveforms acquired with ultrasonic transducers. Results of this advanced measurement spectral tool are found to improve the performance of typical cross-correlation methods and provide reliable and high-resolution estimations.

This study presents an all-optical approach based on an XOR logic gate for encryption by interference and the assistance of multiphotonic effects exhibited by carbon nanotubes. We integrate a Michelson interferometer to propose the encryption system. The key innovation lies in the use of multiwalled carbon nanotubes (MWCNT) to control the XOR operation through intensity-dependent nonlinear optical absorption. We introduce control based on nanosecond nonlinear optical absorption in MWCNT. By measuring irradiance propagation through thin-film samples of MWCNT, we demonstrate a threshold-based binary data recording system that is highly resistant to unauthorized access. The combination of interferometric response, MWCNT-based intensity control, and multicriteria decision analysis through nonlinear absorption presents a powerful and versatile approach to optical encryption. This method has the potential to be a base for secure communication systems and optical computing, with possible extensions to biological computing and microbiology. While challenges in power optimization and scaling remain, this research marks a significant step towards advanced, ultrafast encryption systems.

This study explores the integration of reduced graphene oxide (rGO) into an optoelectronic XOR logic gate to enhance BB84 protocol encryption in quantum communication systems. The research leverages the nonlinear optical properties of rGO, specifically its nonlinear refraction characteristics, in combination with a Michelson interferometer to implement an optoelectronic XOR gate. rGO samples were deposited using the Langmuir–Blodgett technique and characterized in morphology and structure. The optical setup utilized a frequency-modulated laser signal for the interferometer and a pulsed laser system that generates the quantum information carrier. This integration of quantum encryption with nonlinear optical materials offers enhanced security against classical attacks while providing adaptability for various applications from secure communications to quantum AI.

Interstitial Photodynamic Therapy (IPDT) is a promising form of treatment of deep-seated and bulky malignant tumors, based on the lethal cell response to the photochemical reactions when drug is light activated at presence of oxygen. After intravenous administration, the drug is retained selectively by malignant cells, and then, the light is delivered to the target tissue through multiple optical fibers. In order to accomplish an effective internal illumination, laser sources are preferably used because of two important reasons: the laser beam is easily focused to optical fibers, and the monochromatic light can be confined to the narrow absorption band of the drug. In this work we present the design of an irradiation laser system, which involves a 635nm laser diode and a delivering fiber system, for 5-ALA mediated IPDT.