Thursday 24 November 2011

Two chances to meet Simon Marsden

I guess you're familiar with Simon Marsden's atmospheric (if not downright spooky) infrared photographs of ruins and the like. I've recently mentioned his new book on vampires and there are two chances to get a signed copy and meet the man coming up before the New Year.

The first is at the Walcot Gate, off Walcot Street, Bath, Somerset between Tuesday 29th November and Saturday 3rd December 2011 (11am - 5pm). Like the book, the exhibition is called Vampires - The Twilight World and Simon will be on hand throughout the run to answer questions and sign copies.

A little more formal is a talk called Christmas Spirits, at Stubton Hall, near Newark, Nottinghamshire on Saturday 10th December 2011 from 6.30 pm to midnight. It says here ...
Come and listen to internationally famous photographer, author and ghost hunter Sir Simon Marsden talk about his upbringing in haunted houses that so influenced his career. Illustrated with photographic slides he goes on to describe how he created his singular style and the techniques he uses. But most of all share some of the extraordinary adventures he has experienced when travelling in the UK and in foreign lands in search of the undead, which have sometimes been truly frightening.
Here's hoping his stock of infrared film holds up.

Monday 21 November 2011

Long-lasting near-infrared emitter

Via various web sites I've been led to a paper published in Nature Materials [abstract].

Zhengwei Pan, associate professor of physics and engineering at the University of Georgia, Franklin College of Arts and Sciences, and his team have developed a material which will fluoresce in a narrow band around 700nm when excited by any visible wavelength including fluorescent lighting. OK, we all know that 700nm is the boundary between red and near-infrared but the eye's sensitivity to that wavelength is so low that we will usually refer to this as near-infrared. You can see the excitation and emission spectra in the Nature abstract.

What is exciting about this work is that, after a short excitation, the material will continue to emit for a long time ... 'seconds to minutes' will result in more than 360 hours output according to the paper. The material can be fabricated into nano-particles which could bind to cancer cells, enabling visual location of small cancers in the body, it can be made into ceramic discs or even paint in order to provide illumination visible only to people using near-IR sensitive devices. I can see an application to detect whether something has been exposed to light recently.

Apparently the starting point is the trivalent chromium ion, a well-known IR emitter when its electrons return to their ground state after excitation by visible light. Usually the effect lasts only a few milliseconds but this new material embeds the chromium in such a way that the emitted light is trapped and releases the energy more slowly. [More info at EurekaAlert for those of us without a Nature subscription.]

This photo shows Zhengwei Pan (left) and postdoctoral researcher Feng Liu in a darkened room, using only their infrared-emitting ceramic discs as a source of illumination. The phosphorescent material was also mixed into the paint that was used to create the University of Georgia logo behind them. You can just see the 'five-o'clock-shadow' on their faces, a result of near-infrared skin penetration. [Credit: Zhengwei Pan/UGA]

Wednesday 16 November 2011

Nature in a different light

More innovative thermal imaging from Chris Lavers. His Nature in a different light exhibition is at Paignton Library and Information Centre in Devon until December 6th (not Sundays).

The exhibition combines striking thermal images of endangered species coupled with beautiful conventional photographs of the animals. It is the work of Dr Chris Lavers from Plymouth University, Jean and Ray Wiltshire (regular photographers at Paignton Zoo), and Paignton Zoo’s Dr Amy Plowman, and is funded by the Institute of Physics and the British Science Association Bristol and Bath Branch.