Photonics for a Better World

Yosemite National Park offers stunning views of mountain vistas during the day and star-filled skies at night. This view often includes the Milky Way -- invisible to almost one third of Earth’s population due to light pollution. Artificial lighting is restricted in Yosemite, but some areas in the park require lighting, such as parking lots and pathways between buildings. Light pollution can not only have a negative effect on visitors’ experiences, but can also change the natural rhythms of the park’s wildlife. University of California, Merced (UC Merced) graduate student Melissa Ricketts has found a solution – by turning one of her professor’s inventions upside down. In an article from UC Merced’s University News , Ricketts describes what she calls “prescribed irradiance distribution.” Ricketts is a member of UC Solar , a multicampus research institute headquartered at UC Merced headed by Roland Winston, the inventor of nonimaging optics. His compound parabolic concentrato...

A major focus of the International Year of Light and Light-Based Technologies was raising awareness of light pollution. With the rapid dissemination of LED lighting, one unfortunate side-effect is the proliferation of a higher color-temperature illumination. This has many documented negative effects on wildlife behavior and migration, as well as on human circadian rhythms. In addition, scientists are studying further problems in human health that may be indirectly related to different lighting, including higher incidence of some cancers. Meanwhile, cities and towns across the globe enthusiastically switch to LED street lighting. The energy savings are significant, but in news reports of the plans and projects, there is usually no mention of the technical specifics (or “warmth”) of the light. Early bright white LED streetlights were mostly above 4000K, whereas warmer versions are now available, 3000K or below. One problem with extremely bright light is that it impairs vision in da...

Humans have been improving photography since Aristotle ’s first observation of a pinhole camera in 350 BC, with milestones such as the introduction of the Lumière brothers' panchromatic plate in 1894 and Willard Boyle and George Smith ’s invention of the charge-coupled device (CCD) in 1969. Today, improvements to digital single-lens reflex (DSLR) cameras, which combine optics with digital imaging sensors, have introduced astrophotography to the wider public. Since its establishment in 1990, the Hubble Space Telescope has used astrophotography to render inspiring images of planets, stars, and solar systems. In the photo above, Alexander Stepanenko has used astrophotography techniques to capture the aurora borealis -- the northern lights. The fascinating phenomenon is caused by the collision of solar wind and magnetospheric-charged particles in high-altitude atmosphere. Using a DSLR camera (Nikon D-800), Stepanenko captured the photons and thermal noise of the north...