The effect of a 1070-nm continuous and pulsed wave ytterbium
fiber laser on the growth of Saccharomyces cerevisiae single
cells is investigated over a time span of 4 to 5 h. The cells are subjected
to optical traps consisting of two counterpropagating plane
wave beams with a uniform flux along the x, y axis. Even at the lowest
continuous power investigated—i.e., 0.7 mW—the growth of S. cerevisiae
cell clusters is markedly inhibited. The minimum power required
to successfully trap single S. cerevisiae cells in three dimensions
is estimated to be 3.5 mW. No threshold power for the
photodamage, but instead a continuous response to the increased accumulated
dose is found in the regime investigated from
0.7 to 2.6 mW. Furthermore, by keeping the delivered dose constant
and varying the exposure time and power—i.e. pulsing—we find that
the growth of S. cerevisiae cells is increasingly inhibited with increasing
power. These results indicate that growth of S. cerevisiae is dependent
on both the power as well as the accumulated dose at
1070 nm.