Subcategory: Materials Science
Kristopher Liggins - Alabama A&M University
Co-Author(s): B. Rami Reddy and Vernessa Edwards
Now-a-days there is a great interest in developing diode pumped solid state white light emitters, because these are free from pollution, energy efficient and last longer. Our research is concentrated on developing glasses that emit white light under diode laser excitation. The investigation of the research conducted pertains to the yielding of glass that can emit white light when placed under uv-blue diode excitation. For this purpose, we have used 375 and 405 nm diode lasers. Inorganic glasses are made by the melt quenching technique. By doping the glass samples with rare-earth ions, the florescence of the glass is controlled by obtaining specific emission peaks in the red, green, and blue wavelengths. These peaks pertain to the emission of the rare-earth ions in the material when the material is exposed to the laser. To enhance the emission peaks of white light in the material, silver was added to the mixture. After concluding the preparation, the sample was then sanded and polished in order to increase the transparency and smoothness of the sample. To obtain the results, we utilized the following procedures, equipment and software in this study. The sample absorption spectrum in the visible wavelength region was recorded using Cary 3E spectrophotometer. Based on the absorption spectral wavelengths, we selected diode lasers to excite the sample. Under 405 nm excitation the sample revealed orange color emission. However, under 375 nm laser excitation, the sample revealed bright white light. Spectral analysis revealed that 405 nm laser excited Dy3+ and Sm3+ ions which emitted in the orange, red and blue wavelength regions. However, under 375 nm laser excitation the sample emitted red, yellow, green and blue wavelengths. The 375 nm laser was absorbed by Tb3+, Dy3+ and Sm3+ ions. Thus the sample emission appeared to be white in color and the sample glow is very bright. Lifetimes of the excited levels was measured to confirm that the emission is coming from different ions. The spectroscopic details will be discussed in the poster presentation. The emission spectrum was measured using a compact spectrometer. In conclusion found that white light emitting glasses are a viable option for many optical applications. By doping Tb3+, Dy3+ and Sm3+ within the glass we found that the emitting colors result in the emission of white light. This investigation will lead to more research and alterations to the initial samples created.
Funder Acknowledgement(s): NSF RISE
Faculty Advisor: Rami Bommareddi, email@example.com
Role: During the research I was involve in the mixing, grinding, sintering, and polishing of the glass sample. I also took the measurements for the emission and absorption of the glass before and after being polished. Additionally I was involved in background reading to find what which rare-earth ions emitted at specific wavelengths.