Long exposure to ultraviolet A, UVA (315 nm - 400 nm) and ultraviolet B, UVB (280 nm - 315 nm) from the sunlight is harmful to human skin. It can cause unwanted pigmentation, skin aging, wrinkles and cancer. Thus, application of sunscreen lotion is necessary to protect us from these harmful ultraviolet. However, sunscreen lotion does not last for an entire day, its effectiveness degrades over time. In this study, we aim to investigate the effectiveness of various types of sunscreen lotion. The ingredient of the chosen sunscreen includes common ingredient such as ethylhexyl methoxycinnamate and titanium dioxide. In this experiment, ethylhexyl methoxycinnamate show degradation after exposed to tungsten-halogen lamp for 180 minutes. However, mixing titanium dioxide into ethylhexyl methoxycinnamate did improve its stability and protection against UVA and UVB.
In this paper, we proposed a multipurpose graphene all-optical sensor based on the nonlinear effect in a multimode interference (MMI) coupler. The use of a graphene as a core for this device is because of its high optical nonlinearity value and thin layer which makes its bandgap relatively small. Graphene also has a lot of great characteristics to be used as sensor material such as high thermal and electric conductivity, light yet durable and also almost transparent due to its being a single layer atom. The graphene will be sandwiched with a substrate that have a varying value of refractive index. By changing the refractive value of the substrate, an external wave will interact with the input waveguide thus lead to a change in the intensity of the output waveguide which will be analysis for the sensor output. The result shows the high distinguished changes on modal expansion and output distribution in various refractive indices of surrounding layer.
Lasing was observed from ZnO nanorods prepared by a simple method of chemical bath deposition (CBD) on ITOcoated glass substrates. The X-ray diffraction pattern showed a dominant peak for (002) plane typical for good crystalline quality of ZnO grown in the z-direction with a wurtzite structure. Continuous-wave photoluminescence (PL) spectra revealed a peak centered at 380 nm corresponding to the band gap of ZnO. Under pulsed optical pumping, lasing was observed above the nominal PL peak, initially for one mode at 384 nm. Two additional modes at 386 nm and 390 nm was observed when the pumping power is further increased. Threshold was achieved at 0.7 μJ which was 10 times smaller than that reported for powder-based random lasers. In addition, gain pinning was also observed for the dominant mode and the additional two modes appeared upon onset of this gain pining behavior.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.