SPIE Professional January 2010
When innovating with light to improve the world, sometimes it's what you don't see that matters most. Photonics technology is being used to detect gas leaks, help people hear, protect against skin cancer, and produce amazing artwork.
From IR . . .
Methane and other gases are invisible to the unaided eye but can be visually detected using an IR camera.
Detecting gas leaks is important both as a life- and cost-saver. Methane is a potent heat-trapping gas that accounts for as much as a third of the human contribution to global warming. In 2006, the U.S. Environmental Protection Agency estimated that Russia let 427 billion cubic feet of methane escape annually, followed by the United States at 346 billion, Ukraine at 225 billion, and Mexico at 191 billion.
Growing from military applications, IR detectors cost relatively little and save companies money. A clearer view of the worst methane emissions could come next year, when Japan plans to start releasing data from the Greenhouse gases Observing SATellite (GOSAT) that began orbiting Earth in January. GOSAT may be able to identify the top hot spots within a few miles.
It takes more than sunscreen to keep the sun's ultraviolet rays from harming your skin. The type of clothing you wear can offer protection, too—or not. It is not just the type of fiber and the weave of the fabric that matters, but also the color. Ascención Riva of the Polytechnic University of Catalonia and colleagues have addressed the color issue, studying the effects of different dyes on the UV protection provided by lightweight woven cottons.
The researchers chose three fabrics, not dyed, with different initial levels of UV protection based on the weave and other factors. Then they dyed them in varying shades of blue, red, and yellow and measured how much UV radiation was absorbed and transmitted.
They found that red and blue shades performed better than yellow, particularly in blocking UV-B rays, which are the most harmful. Protection increased as the shades were made darker and more intense. And if the initial protection level of the fabric was higher, the darker shades offered even greater improvement.
The researchers say the findings, reported in Industrial and Engineering Chemistry Research, should help fabric and garment manufacturers optimize their products for UV protection.
From Outer Space . . .
Scientists are using LIDAR to monitor forest health from space. Measurements of forest canopy height and under-story yield essential information for many forest management activities and are also barometers for changes in the carbon cycle and the environment generally. This forest biomass can be measured remotely from space.
A hyperspectral imaging LIDAR (LADAR) instrument is being developed to measure forest canopy height and canopy cover/fraction, even above sloping ground.
The Centre for Earth Observation Instrumentation (UK) has provided funding to a number of projects to develop technologies such as LIDAR imaging which can help deliver this important information.
To the Inner Ear
A new study conducted at Medical University Hannover (Germany) published in the Journal of Biomedical Optics last July investigated the use of green laser light to provide localized activation of the cochlea, as measured by eliciting optical-induced auditory brainstem responses.
Laser light can be focused in a controlled manner and may provide more localized sensorineural activation across different frequency regions in the inner ear.
The study demonstrated that visible light can effectively and reliably activate the cochlea without damaging the ear. Further studies are in progress to investigate the frequency-specific nature and mechanism of green light cochlear activation.
The authors, G. I. Wenzel, Medizinische Hochschule Hannover (Germany); Hubert H. Lim, Medizinische Hochschule Hannover (Germany) and Univ. of Minnesota (United States); Kaiyin Zhang, Laser Zentrum Hannover e.V. (Germany); Sven Balster, Medizinische Hochschule Hannover (Germany); Ole Massow, Holger Lubatschowski, Laser Zentrum Hannover e.V. (Germany); Guenter Reuter, Thomas Lenarz, Medizinische Hochschule Hannover (Germany), will present a paper on laser hearing aids Sunday, 24 January at SPIE Photonics West in San Francisco.
Photonics is also making our world more beautiful. For more than 30 years, Nikon has rewarded the world's best photomicrographers who make critically important scientific contributions to life sciences, bio-research, and materials science.
The 2009 winner of the Nikon Small World Photomicrography competition was Heiti Paves of Tallinn University of Technology (Estonia) for his confocal microscope image of the anther of a tiny thale cress plant, the male sex organ of a small flowering plant.
Submissions for the 2010 competition are due 30 April.