Milky way

With a long enough exposure and an open aperture, the Milky Way, with its clouds of dust, becomes revealed in its full glory. This was taken with a 10s exposure at f/1.8, ISO 1600 on a 50mm lens. 

Laser light through a water droplet

I like this photo because it showcases the incredibly rich structure of caustics at the scale where wave interference becomes important. A brilliant network of fold lines, cusps and even high-order umbilic caustics are visible, all described by combining the mathematics of catastrophe theory and wave interference. This structure is possible to see with a simple handheld laser, glass slides, and some patience.

Sunset over glass

What's better than a summer evening by the lake?