Two distinct spatial beam profiles for sealing and cutting were achieved by translating the vessel position 30 mm along the optical axis, thus moving the tissue out of and into the focus for sealing and cutting, respectively. This resulted in a change in the power density ratio (cutting/sealing) by a factor of 2.7. These two linear beams, aligned perpendicular to the vessel direction, are shown in Fig. 2 imaged with an IR spatial beam profiler (Pyrocam III, Spiricon, North Logan, Utah). The seal beam measured 9.5 mm long by 3.0 mm wide (power density of ) and the cut beam measured 9.6 mm long by 1.1 mm wide (FWHM) (power density of ). The vessel sample was sandwiched between a 1-mm-thick front glass slide and a 5-mm-wide back, metal faceplate with a glass slide insert, similar to our previously used bench top setup.29 The gap between the tissue contact surfaces when fully closed was fixed at 0.4 mm in the experimental setup to provide tissue compression closely matching the OPD of the laser wavelength. A force meter (25 LBF, Chatillon, Largo, Florida) then monitored the amount of force applied to the vessel sample, which was held constant at 36 N for this study. Laser energy was delivered in long-pulsed mode first with the seal beam dimensions for 1.0 s to create a thermal seal in the clamped vessel, and then the clamped vessel was translated 30 mm before cutting the vessel with an additional 1.0 s of laser irradiation at the beam focus. This large translation distance was a function of the cylindrical lens’s long focal length required for adequate optical element spacing in our bench top vessel compression setup. The sealing and cutting times of 1 s each were chosen based on earlier preliminary studies, which showed this to be the shortest period of time at maximum laser power that produced both strong seals and consistent cutting of a wide range of blood vessels.