Complex Field Modulation of Incoherent White Light with a Spatial Light Modulator

Holographic display and imaging are usually implemented with coherent lasers, which usually suffer from speckles. Incoherent light sources have long been highly desired for holographic applications, but the corresponding spatial modulation scheme is still lacking. Here we demonstrate a hyperspectral complex field modulation based on a single spatial light modulator (SLM) for an incoherent white light-emitting diode (LED) with a 200 nm bandwidth. The technique encodes the complex fields of multiple wavelengths into a phase hologram. The hologram has an analytical expression and is the superposition of multiple fringe patterns with different frequencies. By tuning the local fringe frequency on the hologram, one can modulate the local output spectrum. The method is applied for sweeping wavelength and projecting color images, where tens of spectral channels are modulated independently. Moreover, the method can achieve complex modulation and is applied in multi-plane holographic projections.