For bio-medical applications pulsed wave laser is preferred as continuous wave laser may be fatal to the cells. As discussed, for the assumption of thermal equilibrium between the electron cloud and the metal lattice to hold, the pulse durations (50 ns, 100 ns, 200 ns and 400 ns) considered in this study are in the order of nanoseconds. Under pulsed wave, the temperature of the nanoparticle fluctuates with time from the beginning and eventually becomes a periodic with the laser after sufficient time. In Figure , the periodic temperature profile of a nanorod under pulsed wave laser of different pulse durations are compared. For a longer pulse duration, the range of the nanorod temperature that varies between the maximum and the minimum limits is wider. Moreover, when the pulse duration is long, the nanoparticles stays in a high temperature for a longer period of time. While for short pulses, the temperature fluctuations are faster. Also, the window of temperature variation is narrower. So, the selection of the right pulse duration is dependent on what kind of temperature profile is required for a specific application. The transient temperature of the surrounding fluid medium heated by the nanoparticle also varies with the nanoparticle without any apparent lag. As illustrated in Figure (b), the periodicities of the temperature variations at two points at 50 nm (point 1) and 100 nm (point 2) distance from the nanorod axis are the same as that of the nanorod. In Figure , the development of temperatures field during one complete pulse (on for 400 ns/ off for 400 ns) is shown. Apparently, the response of the surrounding temperature field to the nanoparticle temperature fluctuations is instantaneous. The steady state temperatures of unconfined nanoparticles has been discussed in section 3.1. For Prandtl number > 1 like the present case of water (Pr ~ 7), the presence of confining walls has a relatively stronger effect on the flow field than the temperature field as the momentum boundary layer is thicker than the temperature boundary layer. When the confining walls have a constant temperature boundary condition, with decreasing distance between the walls and the nanoparticle, the steady temperature also decreases as less heat is retained in the system. Thus, in Figure