It's a short walk from the third floor of the Welch Building on the University of Texas campus to the basement of the Engineering Science Building. That's enough, however, for mid-August in Austin to work its magic. Temperatures above 100 make the stroll a steamy affair.The basement of the building is cool and so is the photonics technology there. The basement houses a 6000-square-foot laboratory, full of several million dollars' worth of femtosecond lasers. It also holds other advanced analytical equipment, such as an atomic force microscope and a transmission electron microscope. The gear is used in physical chemistry research, including femtosecond spectroscopy of ultrafast chemical reaction dynamics in liquids…