Figure 1: Engine cycle and microparticle trajectory in the optical tweezer.
From: A microscopic steam engine implemented in an optical tweezer
(a) Phase diagram to describe the cycle, p0=0.1 MPa, Tcav is the temperature at which the superheated liquid relaxes with the nucleation of a bubble. Tsp is the spinodal temperature or superheat limit at a p0. pc=22 MPa and Tc=373.9 °C are the critical pressure and temperature for water. (b) Microparticle trajectory in the optical tweezer. (1–2) Optical forces attract the particle towards the focus heating it at atmospheric pressure p0, (2–3) increase in speed and heating rate results in superheated liquid at the surface, (3-4-1) explosive vaporization with adiabatic expansion pushes the microparticle close to the initial position.
