Conventional valleytronics relies on two momentum-separated valleys characterized by opposing optical selection rules. However, this bivalley architecture encounters challenges due to intervalley scattering and static selection rules. In this study, we propose a single-valley architecture capable of generating two orthogonal polarization responses, which represent two distinct nonequivalent states. Focusing on the $M$-point valley in a tetragonal lattice with a little group of $D_{2d}$, we demonstrate that uniaxial strain functions as a dual switch. In its unstrained state, the valley is optically inactive, exhibiting no polarized absorption. When strain is applied along the $x$ direction, the symmetry is reduced to $C_{2v}$, activating $x$-polarized absorption and defining one valley state. Conversely, applying strain along the $y$ direction activates $y$-polarized absorption, thereby defining the other state. Crucially, since only one valley is involved, intervalley scattering is entirely absent. Using first-principles calculations on monolayer ${\text{Zr(CuN)}}_2$, we demonstrate this strain-reconfigurable linear dichroism and uncover frequency-encoded orthogonal dichroism. Our findings pave the way for programmable valleytronics anchored in a single valley, effectively overcoming the inherent limitations associated with traditional bivalley systems.

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• Electronic structure
• Valley degrees of freedom
• Valleytronics
• 2-dimensional systems
• Layered semiconductors
• First-principles calculations