  The dynamic dipole polarizabilities for the four lowest triplet states
($2\,^3S$, $3\,^3S$, $2\,^3P$ and $3\,^3P$) of helium are calculated using the
B-spline configuration interaction method. Present values of the static dipole
polarizabilities in the length, velocity and acceleration gauges are in good
agreement with the best Hylleraas results. Also the tune-out wavelengths in the
range from 400 nm to 4.2~$\mu$m for the four lowest triplet states are
identified, and the magic wavelengths in the range from 460~nm to 3.5~$\mu$m
for the $2\,^3S \to 3\,^3S$, $2\,^3S \to 2\,^3P$, and $2\,^3S \to 3\,^3P$
transitions are determined. We show that the tune-out wavelength of $2\,^3S$
state is 413.038 28(3) nm, which corroborates the value of Mitroy and Tang
(Phys. Rev. A 88, 052515 (2013)), and the magic wavelength around 1066 nm for
the $2\,^3S \to 3\,^3P$ transition can be expected for precision measurement to
determine the ratio of transition matrix elements $(2\,^3S \to 2\,^3P) /
(3\,^3P\to 6\,^3S)$.
