Website of Ian M Baker MIET, CEng
Leonardo Ltd (formally Selex) develops and manufactures infrared detectors and cameras at sites in Southampton and Basildon. The company allows me to use the cameras for filming wildlife and assisting with nature projects around Hampshire and the south of England. Some of the videos can be accessed from this website.
Currently my role at Leonardo is developing infrared detectors for Space and astronomy
These images show what an infrared detector looks like. We grow crystals of cadmium mercury telluride atom by atom and fashion them into pixels that look like cones. They are then indium bump bonded to a special IC and packaged.
They get put into miniature Stirling coolers (left) to cool them to liquid air temperatures. These cooler assemblies then go into modules and cameras like this:
Modern cooled infrared cameras produce amazing images like this. The colour images are from our Merlin camera developed by Basildon for wildlife filming. The central one is from our SuperHawk camera which has the smallest pixel size of any commercial camera.
These cameras have cooled focal planes so the infrared detectors are so sensitive they can be operated with powerful zoom optics for filming from a distance.
There are many quite surprising observations that cannot be easily explained
It was noticed that many natural predators of rodents had adaptations to hide there own infrared signature hinting that rodents could sense infrared. The sensors were found in the fur. They are the so-called guard hairs that act as infrared antennas directing infrared to bolometric sensors at the base of the hair. The photonics is quite straightforward to analyse. and the photo below shows a small section (wide hair).
The mystery of how bats and other energetic animals thermoregulate was taken a step further when it was shown that bats wings are cold and do not participate in cooling. The fur is responsible for cooling. The other two hairs below have been shown to be infrared radiators but tuned to a chemi-luminescent wavelength at 16.25um. In the bulb of these hairs is an optical cavity with a chemical reaction chamber. Enzymes catalise the bicarbonate reaction, a powerful cooling reaction that cools the blood. The chemi-luminescent infrared is radiated away by these so-called zigzag hairs.
Does it have any practical value?
These hair structures have been the subject of rapid evolution possibly for 250my and are complex. Manipulating infrared photons at the scale of the wavelength and in 3D is the direction of all modern photonics. There are complex bragg gratings, surface holograms, optical filters and polarising structures that could be applied telecoms and optical computers. This is a rich area for bio-inspiration. When mammal experts engage with this interpretation of hair anatomy it could provide new insights into physiology and even the evolution of small animals.
Acknowledgements
I would like to recognise the help and support of many people especially my daughter Nikki for the website and grandaughter Kaia Mai who is “bringer of dead things!”. Thanks to Nik Knight and the Hampshire Bat Group for many evenings filming bats roosts, to Peter and Sam Whieldon for filming owls, to Debbie Harwood for flying a pip around my lounge to film its fur heat, to many helpers during often freezing nights filming especially Peter Thorne and Amy Hearst. I have had a lot of help on the camera operation from Stuart Ashley at Basildon and Dan Owton at Southampton. Thanks for fur samples from Paul Hope, Simon Bradley, Megan John and Marissa Parrot of Melbourne University. Thanks especially to son Dr David a Post Doc specialist in Ecology who adds the bio-science and in general keeps a more level head than me. And of course very grateful for the company Leonardo for allowing me to use these amazing cameras.
Last edited 10th April 2020