Authors notes

Website of Ian M Baker  MIET, CEng

Leonardo Ltd (formally Selex) develops and manufactures infrared detectors and cameras at sites in Southampton and Basildon. This has given me the opportunity to use some powerful thermal imaging cameras to film wildlife and try to understand the infrared world of mammals and birds. If you work in the field long enough you get very familiar with infrared engineering and it was quite a surprise to find what appears to be very sophisticated infrared engineering in small animals, much of which we still do not understand. This is the subject of the website.

My day job is designing infrared detectors and astronomy is one of the most interesting fields. Here is Gert Finger who pioneered the use of our infrared detectors in telescopes and the late Donald Hall who sadly passed away in early 2020. Don was a major figure in astronomy who managed the Hawaii constellation of telescopes and its instrumentation and worked with me for 8 years on our very advanced sensors for the next generation of telescopes. Don showed me around Hawaii and gave me a VIP tour around the worlds largest telescope, Keck 1. 

Slide2

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. 

Slide1

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:

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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. 

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In my spare time I get to use some of Leonardo’s thermal imaging cameras to film wildlife. I work with people like Nik Knight, Chairman of Hampshire Bat Group, who has introduced me to private bat roosts, and Peter Whieldon who allows me to film his owls. The infrared detectors at the heart of these cameras are so sensitive you can use powerful zooms and short exposures so flying animals can be filmed in flight for the first time. 

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The emphasis of my interest is explaining the physics of the videos and stills. Often images, such as these below, reveal heat patterns that are not easy to explain. This means there is new knowledge to discover but you need to dig deeper with microscopy. 

Slide7

Imagine my surprise at looking at mouse hair under a microscope and seeing common optical structures: gratings, antennas and sensors. The photograph below shows a guard hair that has regular cells tuned to the main thermal infrared wavelength making it a candidate for an infrared sensor. The other two hairs have gratings that when mapped for the whole hair can be interpreted as a radiating antenna for cooling the animal during energetic activity. Small mammals can decide the function of the hair, either insulating for keeping warm or radiating. We only have the infrared engineering to predict the presence of this mechanism so much more work is needed to complete the model.

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This work needs to be reported because it needs experience to identify infrared adaptations and there are so few infrared scientists in the world that also have an interest in the natural world that it may be not repeat.

Does it have any practical value?

This is a rich area for bio-inspiration. The degree of detail in the fur of fast-breeding animals could inspire antenna design, infrared detectors, optical concentrators and even quantum optical devices. 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 expensive cameras.

 

Last edited 10th April 2020