this code simulating laser output power respect to time for different laser dimensions length, width and diameter of cavity. Can anyone explain indetail this part of the code

LL=[250E-6, 250E-6, 500E-6, 500E-6, 250E-6, 500E-6]; %cavity length

ww=[5E-6, 10E-6, 5E-6, 10E-6, 5E-6, 10E-6]; %cavity width

dd=[0.2E-6, 0.2E-6, 0.2E-6, 0.2E-6, 0.1E-6, 0.1E-6]; %cavity diameter

for iii=1:length(LL)

ti = 0;

tf = 2.50E-9;

tspan=[ti tf];

y0=[0; 0; 0];

V=LL(iii)*ww(iii)*dd(iii);

[T,Y]= ode45(@(t,y) rate_eq(t,y,V),tspan,y0);