  We report on a novel experimental scheme to generate continuous-wave (cw),
high power, and higher-order optical vortices tunable across mid-IR wavelength
range. Using cw, two-crystal, singly resonant optical parametric oscillator
(T-SRO) and pumping one of the crystals with Gaussian beam and the other
crystal with optical vortices of orders, lp = 1 to 6, we have directly
transferred the vortices at near-IR to the mid-IR wavelength range. The idler
vortices of orders, li = 1 to 6, are tunable across 2276-3576 nm with a maximum
output power of 6.8 W at order of, li = 1, for the pump power of 25 W
corresponding to a near-IR vortex to mid-IR vortex conversion efficiency as
high as 27.2%. Unlike the SROs generating optical vortices restricted to lower
orders due to the elevated operation threshold with pump vortex orders, here,
the coherent energy coupling between the resonant signals of the crystals of
T-SRO facilitates the transfer of pump vortex of any order to the idler
wavelength without stringent operation threshold condition. The generic
experimental scheme can be used in any wavelength range across the
electromagnetic spectrum and in all time scales from cw to ultrafast regime.
