Figure 3. Four-wavelength therapeutic laser device
3. Research and Development of Lighting Devices for Biological and Agricultural Applications
a. Energy-efficient chrysanthemum lighting system and device
Fabrication high-power LEDs system with uniform power density distribution were employed to replace conventional lamps (tungsten lamps, compact fluorescent lamps) and successfully applied in chrysanthemum cultivation with energy saving, improved quality production and economic efficiency
b. Solar light-harvesting device integrated with LED sources for plant propagation and cultivation
Figure 4. Plant propagation microclimate chamber using a hybrid solar–LED lighting system: the system is capable of automatically compensating LED light intensity according to solar irradiance fluctuations to maintain stable illumination, while also allowing preset control of light intensity and photoperiod.
A solar–LED hybrid lighting system was developed for plant tissue culture. The system features dual-axis solar tracking and LED intensity control to compensate for irradiance fluctuations, maintaining stable illumination. Experimental results showed energy savings of 54.3% on sunny days and 38.9% on cloudy days. Application trials with Anoectochilus roxburghii and Phalaenopsis demonstrated its potential for reducing energy consumption in plant propagation.
c. Application of LED lighting technology to enhance yield and quality of basil (Ocimum basilicum)
The study identified supplemental LED lighting conditions for basil (Ocimum basilicum, an essential-oil-bearing medicinal plant) that produced significant differences in biomass accumulation and essential oil yield. The maximum value increased by approximately 1.8 times compared to the control, surpassing previously reported results, under two conditions:
(i) 71% Red (660 nm), 20% Blue (445 nm), 9% UVA (365 nm) at 120 μmol·m⁻²·s⁻¹ for 6 h/day.(ii) 43.5% Red (660 nm), 43.5% Blue (445 nm), 8% Green (530 nm), 5% Far-red (730 nm) at 100 μmol·m⁻²·s⁻¹ for 6 h/day.
In this study, the content of methyl chavicol (the principal compound in basil essential oil) reached the highest level. These findings demonstrate the potential of LED-based lighting technology for large-scale applications in optimizing and enhancing the quality of essential oil crop production.
4. Achievements in Applied Spectroscopy
a. Research on optical characteristics and processing technology of gemstones and minerals of Vietnam
Study and publishing characteristic data of Vietnamese gemstones and processing technology of gemstone such as Ruby, Sapphire, Spinel, Emerald, Quartz, Topaz, Zircon...
b. Photonic intergrate materials, optoelectronic components used in optical information -- Research on nonlinear optical characteristics of glass materials:
+ Research and fabrication of planar waveguide components of Aluminosilicate, TitaniumOxide, Silica glasses containing rare earth ions and CdS, PbS semiconductor microcrystals for application in integrated photonic circuits.
+ Research on hole-burning characteristics of Aluminosilicate and Borosilicate glass doped with RE to develop a new optical memory with high capacity of 10^12 bits/cm2
Figure 5. Some of Gem anf mineral sample of Viet Nam (Yen Bai, Nghe An, Tay Nguyen) and published scientific literature on VietNam’s gemstones and minerals
Figure 6. Some images of planar wave guide samples of Aluminosilicate, Titaniumoxide, guide laser radiation 465, 488, 514 and 632.8 nm