Effects of near-infrared laser and superluminous diode irradiation on Escherichia coli division rate

Abstract

An investigation is conducted of the effect of a 1300-nm continuous-wave (CW) laser diode 950-nm modulated superluminous diode which had a fixed average power density of 1.2*10/sup 3/ W/m/sup 2/ at all variable repetition rates of 2, 26, 700, 1000, and 5000 Hz and had an equivalent pulse duration of 410, 31.1, 1.15, 0.82, and 0.16 ms, respectively. The effect of both diodes on the rate of Escherichia coli WP2 division was examined. It was found that the radiation of the CW mode of the 1300-nm laser diode increased the division of E. coli in the dose range of 0.9-9.0 J/cm/sup 2/. The 950-nm pulsed irradiation increased or inhibited the division rate of bacteria depending on the pulsing frequency and/or pulse duration.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>