Extended Data Table 1 List of signals picked up by the photo-detector

From: Light-wave-controlled Haldane model in monolayer hexagonal boron nitride

  1. These signals are sorted by their respective wavelength and non-linear processes involved in giving rise to it. Here, ω refers to λ = 2 μm. The signals at frequencies other than 3ω are all rejected by high extinction ratio spectral filters. Other components are marked with a corresponding blocking method, and they are as follows: † Rejected by lock-in filtering or by helicity filtering of light. ‡ Rejected based on selection rules of bicircularly polarized light. * Rejected based on helicity filtering of light. ** Rejected based on modulation with trefoil pump rotation. Only the signal arising from the valley hall effect is let through. For ω arm chopping, the 3ω signal possessing the helicity of 2ω pump component is detected background free. For 2ω arm chopping, the 3ω signal possessing the helicity of ω pump component is detected background free.
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