LEDs offer numerous benefits due to possibility of different operation modes. Optical parameters of light emitting diodes strongly depend on the operation regime that you choose.
QCW means that an LED is switched on only for certain time intervals, which are short enough to reduce thermal effects significantly, but still long enough that the LED process is close to steady state. We recommend using pulse modes with duty cycle 50% or 25% to receive maximum average power. These modes provide signal modulation at certain frequency and allow obtaining higher output intensity than in case of using hard CW (continuous wave) mode. Therefore hard CW is not recommended.
Pulse mode with short pulse time (less than 50 ms) helps obtaining the maximum peak power.