  We propose neutrino mass spectroscopy using Er$^{3+}$:Cs$_2$NaYF$_6$ or
:Y$_2$O$_3$ crystal placed in hollow of a Bragg fiber as a target system.
Unknown neutrino parameters and properties such as the lightest neutrino mass,
Majorana/Dirac distinction, and CP violating phases can be explored by
measuring scattered photons ($\gamma$) along the excitation (and fiber) axis by
varying Raman trigger ($\gamma_0$) directions, in Er$^{3+}$ de-excitation
process from $|e\rangle $ state to $|g\rangle $ state; $|e\rangle \,, |
e\rangle + \gamma_0 \rightarrow | g\rangle + \gamma + \nu_i\bar{\nu}_j$,
$\nu_i\,, i = 1, 2,3$ being a mass-resolved neutrino state. Rates and required
level of QED background rejection are calculated using measured data of the
target system.
