Curator's Take
This article demonstrates that commercially available transmissive spatial light modulators can already support a full universal gate set on orbital‑angular‑momentum qubits with simulated fidelities above 99 percent, closing the gap between laboratory prototypes and scalable photonic hardware. By grounding the noise model in manufacturer specifications rather than fitting parameters, the authors provide a realistic benchmark that aligns closely with the best experimental results reported to date and highlights 450–532 nm as the sweet spot for low‑error operation. The work suggests that near‑term photonic quantum processors could be built from off‑the‑shelf SLMs, though further mitigation of twisted‑nematic and phase‑wrap noise will be needed before fault‑tolerant thresholds are reached.
— Mark Eatherly
Summary
Spatial light modulators (SLMs) have emerged as reconfigurable platforms for photonic quantum information processing, offering software-defined control over the orbital angular momentum (OAM) of light encoded in Laguerre-Gaussian (LG) beams. This paper presents a comprehensive simulation and hardware-grounded fidelity analysis of quantum gate operations implemented on the HOLOEYE LC 2012 transmissive SLM. A realistic three-channel noise model comprising 8-bit quantisation noise, twisted-nematic (TN) electronic and thermal noise, and phase-wrap clipping error is obtained from the manufacturer's datasheet without free-parameter fitting, yielding a total noise of $σ_{\text{total}} = 92.4\text{mrad}$. The complete universal single-qubit gate set $\{X, Y, Z, S, T, H\}$ and two-qubit entangling gates $\{\text{CNOT}, \text{CZ}, \text{SWAP}\}$ are simulated on a $512 \times 512$ computational grid. Results show that predicted gate fidelity are in the range of $F = 0.9914\text{--}0.9936$, with fork grating gates limited primarily by TN noise and phase gates achieving higher fidelity owing to zero phase-wrap clipping error. In addition, Bell state preparation via the H-CNOT circuit achieves $F(Φ^+) = 0.9914$ after two SLM interactions. We benchmark our obtained results against six published experimental studies spanning the 78%--99.6% fidelity range. Finally, a wavelength-dependent analysis identifies 450--532 nm operation as the optimal regime for this device.