As soon as we received the finished prototype, we were struck by the brightness of the images. This is due to a combination of the low magnification (4x) and the high cone angle of the lens, which means that it captures light emitted by the specimen over a wide angle and therefore efficiently. When we examined a human flea, similar to that shown in Robert Hooke’s 1660 publication, we were able to image the faint fluorescence emission from the unstained specimen.

In the diagram below, our fluorescence image from the giant lens is placed alongside Hooke’s engraving.