It is common to define the coherent states in quantum optics with  and states with fixed number of photons with .
ɪɾ ɪz kˈɑːmən tə dᵻfˈaɪn ðə koʊhˈɪɹənt stˈeɪts ɪn kwˈɔntəm ˈɑːptɪks wɪð ænd stˈeɪts wɪð fˈɪkst nˈʌmbɚɹ ʌv fˈoʊtɑːnz wɪð .