The laser system (Fig. 1 A) is similar to that previously used for local heat shock24 (link),25 (link), and is built around an inverted microscope (Nikon TE-2000). A thermoelectrically cooled, fiber-coupled diode laser (Fitel FOL1425RUZ-317, 1480 nm wavelength) generates a beam that emerges from the fiber end and is collimated by a lens. The beam reflects from a dichroic beam splitter, enters an objective lens (Nikon PLAN APO 60X, NA 1.4, oil immersion), and is focused onto a sample slide (Fig. 1 B). A computer, pulse generator, and laser current source (Opto Power OPC-PS03-A) drive the laser to generate pulses of the specified frequency and duration.
We made several modifications to the previous heat shock system24 (link),25 (link) to adapt it for laser ablation. First, we replaced the original collimating lens (focal length f = 75 mm) with one of smaller focal length (f = 11 mm) in order to create a smaller diameter beam, allowing a larger fraction of the beam power to transmit through the objective and reach the sample. Second, the laser power output was increased from 260 to 400 mW. Third, we adjusted the pulse duration and count as described above.
We made several modifications to the previous heat shock system24 (link),25 (link) to adapt it for laser ablation. First, we replaced the original collimating lens (focal length f = 75 mm) with one of smaller focal length (f = 11 mm) in order to create a smaller diameter beam, allowing a larger fraction of the beam power to transmit through the objective and reach the sample. Second, the laser power output was increased from 260 to 400 mW. Third, we adjusted the pulse duration and count as described above.
Free full text: Click here
