Table 1.

Mean value of measurements for LEDs, power (P) in mW and power density ($P_g$) in mW/cm${}^2$, for 3 diodes in a cluster. Square modulation frequencies of 10 and 40 Hz and continuous generation (DC) were tested for different power levels (PL).

Type/Measure	10 Hz/PL1	10 Hz/PL2	10 Hz/PL3	10 Hz/PL4	40 Hz/PL2	40 Hz/PL4	DC/PL4
P(mW)	1	$3.3$	10	$21.0$	$3.9$	$21.0$	39
$P_g$ (mW/cm${}^2)$	$1.3$	$4.2$	$12.7$	$26.8$	$5.0$	$26.8$	$49.7$