In the free-electron laser the intensity increases exponentially with the number of electrons.
ɪ n ð ə WORD_BOUNDARY f ɹ iː ɪ l ɛ k t ɹ ɑ n WORD_BOUNDARY l eɪ z ə ɹ WORD_BOUNDARY ð ɪ WORD_BOUNDARY ɪ n t ɛ n s ɪ t i WORD_BOUNDARY ɪ ŋ k ɹ iː s ɪ z WORD_BOUNDARY ɛ k s p ə n ɛ n ʃ ə l i WORD_BOUNDARY w ɪ ð ð ə WORD_BOUNDARY n ʌ m b ə ɹ ɹ WORD_BOUNDARY ʌ v WORD_BOUNDARY ɪ l ɛ k t ɹ ɑ n z WORD_BOUNDARY