Optics and Photonics Journal 

About: Optics and Photonics Journal is an academic journal published by Scientific Research Publishing. The journal publishes majorly in the area(s): Laser & Photonic-crystal fiber. It has an ISSN identifier of 2160-8881. It is also open access. Over the lifetime, 537 publications have been published receiving 2806 citations. The journal is also known as: OPJ.

Gold Nanoparticles: Acceptors for Efficient Energy Transfer from the Photoexcited Fluorophores

Abstract: The citrate reduction method of synthesis of gold nanoparticles (AuNP) is standardized with the assistance of instruments like spectrophotometer and TEM. A correlation has been developed between the particle diameter and the fractional concentration of the reductant. This enables one to assess the diameter of the AuNP to be synthesized, in advance, from the composition of the reaction mixture and the diameter of the synthesized particles can be confirmed simply from spectrophotometry. Further, it has been demonstrated that the synthesized AuNPs serve as excellent acceptors for a super-efficient energy transfer (ET) from the donor coumarin 153, leading to a quenching of fluorescence of the latter. The Stern-Volmer constants determined from the fluorescence lifetimes are in the range 107 - 109 mol-1·dm3 and are orders of magnitude higher than the normal photochemical quenching processes. The energy transfer efficiency increases radically with an increase in the size of the metal nanoparticle. The highly efficient energy transfer and the variation of the efficiency of the ET process with a variation of the particle size is ascribed to a large enhancement in the extinction coefficient and an increase in the spectral overlap between the plasmon absorption band of AuNPs and the fluorescence spectrum of C153 with an increase in the size of the nanoparticles. The impact of the work remains in providing a demonstration of a super quenching effect of the AuNPs and projects that they can be exploited for developing biosensors with high degree of sensitivity, if tagged to the biomacromolecules.

Effect of Experimental Parameters on the Fabrication of Gold Nanoparticles via Laser Ablation

Abstract: In this study we report the effect of laser parameters such as laser energy, laser wavelength as well as focusing condition of laser beam on the size and morphology of the gold nanoparticles (GNPs) prepared in deionised water by pulsed laser ablation. The optimum conditions at which gold nanoparticles obtained with controllable average size have been reported as these parameters affected on the size, distribution and absorbance spectrum. Effect of energy was studied. The laser energy was divided into three regions (low, middle and high). A noteworthy change was observed at each region, as the average size changed from 5.9 nm at low energy to 14.4 nm at high energy and the gold nanoparticles reached a critical size of 8 nm at 100 mJ. The Effect of the wavelength on the particle size was examined at 1064 nm, 532 nm. It was found that, the optimum ablation laser wavelength was 1064 nm. Finally, significant results obtained when the effect of focusing conditions studied.

Comparative Study of the One Dimensional Dielectric and Metallic Photonic Crystals

Abstract: The optical transmission properties of two types of photonic crystals have been analyzed by using the transfer matrix method. The first one is the dielectric photonic crystal (DPC), and the second is the metallic photonic crystal (MPC). We found the dielectric and metallic photonic crystals have different transmission spectra. The effect of the most parameters on the transmission spectra of the dielectric and metallic photonic crystals has been studied.

Quantification by Signal to Noise Ratio of Active Infrared Thermography Data Processing Techniques

Abstract: In this paper, the use of a signal to noise ratio (SNR) is proposed for the quantification of the goodness of some selected processing techniques of thermographic images, such as differentiated absolute contrast, skewness and kurtosis based algorithms, pulsed phase transform, principal component analysis and thermographic signal reconstruction. A new hybrid technique is also applied (PhAC—Phase absolute contrast), it combines three different processing techniques: phase absolute contrast, pulsed phase thermography and thermographic signal reconstruction. The quality of the results is established on the basis of the values of the parameter SNR, assessed for the present defects in the analyzed specimen, which enabled to quantify and compare their identification and the quality of the results of the employed technique.

Light-Emitting Diodes (LEDs) for Miniature Hydroponic Lettuce

Abstract: There is growing concern about food safety, environmental impact, and efficient energy usage in agricultural production systems. Producing lettuce under artificial lighting could be a solution addressing these concerns. Light-emitting diodes (LEDs) offer the advantages of a narrow light spectrum, low power consumption, and little heat production. The objective of this study was to determine the effects of different light sources on the growth of miniature “Tom Thumb” butterhead lettuce in a non-circulating hydroponic system. Lettuce seedlings, started in Oasis Horticubes, were transferred to net pots in containers with a hydroponic nutrient solution. The lettuce was grown in a lab under three light treatments—blue LEDs, red LEDs, and fluorescent lights. At the end of the study, fluorescent lights resulted in greater root dry weight than blue LEDs and red LEDs. Total plant dry weight under fluorescent lights was greater than under red LEDs. There were no significant differences in shoot dry weight and plant height among the treatments. Percent partitioning of dry weight to shoots was greatest with red LEDs, followed by blue LEDS, and fluorescent lights. Percent partitioning of dry weight to roots was greatest with fluorescent lights, followed by blue LEDS, and red LEDs. Leaf chlorophyll content was greater under blue LEDs and fluorescent lights than red LEDs. The pH of the nutrient solution of the blue LED and the fluorescent light treatments were greater than the red LED treatment. Electrical conductivity of the nutrient solution of the fluorescent light treatment was greater than the blue LED treatment and the red LED treatment. In conclusion, LEDs could provide an alternative lighting source for miniature lettuce production.