The effect of using external frequency converters on the luminescence intensity of an Nd:YAG crystal is studied. The crystal is illuminated by light-emitting diode (LED) with and without Y3Al5O12:Ce3+ material as an external converter. Obtained experimental results show that the luminescence intensity of Nd:YAG crystal increased by 1.5 times when Nd:YAG crystal is illuminated by LED together with color converter based on Y3Al5O12:Ce3+ demonstrating that external frequency converters can be a potential candidate for creating more efficient solar or LED pumped lasers.