by Louise Mayor
Earlier this month, I and some of my colleagues – Kate Gardner, Margaret Harris and Dens Milne – braved the back streets of Bristol on a very important mission: to bring the readers of Physics World magazine a slightly-more-innovative-than-usual image on the front cover.
We were looking for something a bit different for the May issue of Physics World. This month we are marking the 50th anniversary of the laser by bringing readers top features from a host of eminent laser scientists, as well as a snazzy laser timeline. We needed a front cover that would do it justice.
Our brain wave was “laser-writing”. It would involve the four of us congregating in a darkened room, photographing a blank wall using a camera set to have a long exposure. We would write our chosen phrase on the wall using a red laser pen and capture this on camera. The relevancy would be immense – an image made of pure laser light, just the thing to introduce our laser special issue. Great idea, right?
Full of anticipation, after a drawn-out meal at the local curry house while we waited for darkness, we embarked on our mission. In a dark room we set up our digital SLR camera on a tripod. We used an exposure of tens of seconds to capture each individual alphanumeric character that we needed; these could then be later combined into words. And hey presto! … Hey presto? … Peering at the camera’s digital display, we realised that the effect was not as good as we’d hoped. The laser dot was so small in comparison to the size of the characters that the result appeared spindly.
But fret we did not, as we had back-up. We also tried using a torch (see I ♥ LASER image, top), and an array of bluish-white LEDs. The LEDs became the tool of choice that would eventually make the front cover with the “The laser at 50” image shown right. Note that the issue itself is available as a free pdf download.
We also tried to go a bit more arty, and took to the dimly lit streets. Our best outdoor shot is shown above; the venue was a fenced-up disused garage. If you are interested in trying this sort of thing yourself, take a look at this great guide to light-graffiti.
We hope that you enjoy our efforts!