  The research feld of magnonics proposes a low-energy wave-logic computation
technology based on spin waves to complement the established CMOS technology
and provide a basis for emerging unconventional computation architectures.
However, magnetic damping is a limiting factor for all-magnonic logic circuits
and multi-device networks, ultimately rendering mechanisms to effciently
manipulate and amplify spin waves a necessity. In this regard, parallel pumping
is a versatile tool since it allows to selectively generate and amplify spin
waves. While extensively studied in microscopic systems, nano-scaled systems
are lacking investigation to assess the feasibility and potential future use of
parallel pumping in magnonics. Here, we investigate a longitudinally magnetized
100 nm-wide magnonic nano-conduit using space and time-resolved micro-focused
Brillouin-light-scattering spectroscopy. Employing parallel pumping to generate
spin waves, we observe that the non-resonant excitation of dipolar spin waves
is favored over the resonant excitation of short wavelength exchange spin
waves. In addition, we utilize this technique to access the effective spin-wave
relaxation time of an individual nano-conduit, observing a large relaxation
time up to (115.0 +- 7.6) ns. Despite the significant decrease of the pumping
effciency in the investigated nano-conduit, a reasonably small threshold is
found rendering parallel pumping feasible on the nano-scale.
