Activation of blood platelets is the main process in normal hemostasis. Unfortunately, it also makes a great contribution to the development of cardiovascular diseases. In this work, we study activation dynamics using cytosolic calcium probe. To increase the accuracy of dynamic measurements, we present a method for optical activation of single platelets in suspension. It is achieved by the use of photolabile "caged"activation agonists. In our earlier works, the use of such compounds resulted in precise measurement of early activation dynamics. However, relatively large irradiation dose was needed to achieve the activation of significant fraction of cells. Here we show that dual-agonist stimulation dramatically increases the activation probability, resulting in increased and reliable activation with 10-to-50-times less irradiation dose as compared to our previous report.