Abstract. In this paper, we present an investigation into the dependence of phosphorescence spectra of cooled organic substances on various excitation wavelengths, building on our previous discussions in OPAL’2024 and OPAL’2025 regarding the potential of creating analog optical logical cells in active media cooled to cryogenic temperatures using complex organic compounds. Our findings highlight the feasibility of developing compact optical computing elements based on analogs of the Shpolsky matrix, utilizing a carbon matrix of solid solutions cooled to liquid nitrogen temperature and a monocrystalline Gd₃Ga₃Al₂O₁₂:Ce (GAGG:Ce) scintillator-transducer. To advance this technique, it is crucial to understand the physical nature of optical transitions in cooled organic media, which exhibit extra-long visible spectrum phosphorescence lasting up to 5-30 seconds for different substances.
For this purpose, we examined the phosphorescence spectra of various organic substances cooled to cryogenic temperatures under excitation wavelengths ranging from 250-315 nm using UV LEDs, while also investigating the time dependence and magnetic field influence on these spectra. Furthermore, the article explores the potential of creating analog optical computing cells in such cooled active media, integrating organic compounds and scintillating crystals. Phosphorescence was initiated by multiple UV LEDs, each operating independently under distinct electrical signals. Preliminary results of analog summation and integration of optical phosphorescence signals are presented, and the application of this analog process to solving Fourier differential equations is discussed. The possibility of using the investigated composite samples as contact optical sensors for temperature measurements is also considered.
Keyword: Ultralong phosphorescence, Organic molecules, Optical temperature sensors, Cryogenic temperature, Shpolsky, GAGG:Ce transducer, Optical computing
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