  First experimental results from a room-temperature table-top phase-sensitive
axion haloscope experiment are presented. The technique exploits the
axion-photon coupling between two photonic resonator-oscillators excited in a
single cavity, allowing low-mass axions to be upconverted to microwave
frequencies, acting as a source of frequency modulation on the microwave
carriers. This new pathway to axion detection has certain advantages over the
traditional haloscope method, particularly in targeting axions below 1 $\mu$eV
(240 MHz) in energy where high volume magnets are necessary. At the heart of
the dual-mode oscillator, a tunable cylindrical microwave cavity supports a
pair of orthogonally polarized modes ($\text{TM}_{\text{0,2,0}}$ and
$\text{TE}_{\text{0,1,1}}$), which, in general, enables simultaneous
sensitivity to axions with masses corresponding to the sum and difference of
the microwave frequencies. The results place axion exclusion limits between
7.44 - 19.38 neV, excluding a minimal coupling strength above $3\times 10^{-3}$
1/GeV, and between 74.4 - 74.5 $\mu$eV, excluding a minimal coupling strength
above $10^{-2}$ 1/GeV, after a measurement period of two and a half hours. We
show that a state-of-the-art frequency-stabilized cryogenic implementation of
this technique may achieve competitive limits in a large range of axion-space.
