Multi-spectral vortex beam generation using phase-calibrated liquid crystal spatial light modulator

Optical phase control through a Liquid crystal (LC) spatial light modulator (SLM) are wavelength-dependent, which causes limitations in the modulation of multiple wavelengths simultaneously. Efforts have been made to utilize SLM for multi-spectral light modulations owing to their several applications, such as digital holography, material processing, optical tweezers, cryptography, and communications. However, accurate multi-wavelength phase modulation has not been reported yet. The present study demonstrates a novel technique to utilize parallel-aligned LC SLMs for the modulation of multiple wavelengths simultaneously through single-encoded computer-generated holograms (CGH). Experimental results have been demonstrated that verify the simultaneous generation of optical vortex with wavelengths of 532 nm and 635 nm. The proposed technique can be useful in various optical systems that require multispectral modulation.