  We study the interplay of electron and photon spin in non-reciprocal
materials. Traditionally, the primary mechanism to design non-reciprocal
photonic devices has been magnetic fields in conjunction with magnetic oxides,
such as iron garnets. In this work, we present an alternative paradigm that
allows tunability and reconfigurability of the non-reciprocity through
spintronic approaches. The proposed design uses the high-spin-orbit coupling of
a narrow-band gap semiconductor (InSb) with ferromagnetic dopants. A
combination of the intrinsic and a gate-applied electric field gives rise to a
strong external Rashba spin-orbit coupling (RSOC) in a magnetically doped InSb
film. The RSOC which is gate alterable is shown to adjust the magnetic
permeability tensor via the electron g-factor of the medium. We use electronic
band structure calculations (k$\cdot$p theory) to show the gate-adjustable RSOC
manifest itself in the non-reciprocal coefficient of photon fields via shifts
in the Kerr and Faraday rotations. In addition, we show that photon spin
properties of dipolar emitters placed in the vicinity of a non-reciprocal
electromagnetic environment is distinct from reciprocal counterparts. The
Purcell factor (F$_{p}$) of a spin-polarized emitter (right-handed circular
dipole) is significantly enhanced due to a larger g-factor while a left-handed
dipole remains essentially unaffected. Our work can lead to electron spin
controlled reconfigurable non-reciprocal photonic devices.
