  Recently H$_3$LiIr$_2$O$_6$ has been reported as a spin-orbital entangled
quantum spin liquid (QSL) [K. Kitagawa et al., Nature {\bf 554}, 341 (2018)],
albeit its connection to Kitaev QSL has not been yet identified. To unveil the
related Kitaev physics, we perform the first Raman spectroscopy studies on
single crystalline H$_3$LiIr$_2$O$_6$ samples. We implement a soft chemical
replacement of Li$^+$ with H$^+$ from $\alpha$-Li$_2$IrO$_3$ single crystals to
synthesize the single crystal samples of the iridate second generation
H$_3$LiIr$_2$O$_6$. The Raman spectroscopy can be used to diagnose the QSL
state since the magnetic Raman continuum arises from a process involving pairs
of fractionalized Majorana fermionic excitation in a pure Kitaev model. We
observe a broad dome-shaped magnetic continuum in H$_3$LiIr$_2$O$_6$, in line
with theoretical expectations for the two-spin process in the Kitaev QSL. Our
results establish the close connection to the Kitaev QSL physics in
H$_3$LiIr$_2$O$_6$.
