Independent controlling of polarization states of two beams with different wavelengths

Polarization systems allow creating a variety of devices with required polarization characteristics. Ordinarily, polarization systems are used to control polarization for only one wavelength. With such a system, to modify polarizations of two beams with different wavelengths requires the whole system rebuilding or reconstruction. However, in experimental optics, there is a need for devices for continuous, simultaneous and independent transformations of polarization for multiple wavelengths. We propose a new method for independent polarization control of two light beams with different wavelengths. We show here that such polarization systems should consist of not less than four phase elements, including birefringent plates with controlled axis orientation relative to each other and/or liquid crystal cells with the fixed axis orientation but controlled phase retardations. To demonstrate our approach, we have designed such a four-component system that functions as a half-wave plate for the first wavelength and a retardation plate with an arbitrary phase retardation for the second wavelength. The theoretical analysis presented here supports our approach and shows it’s validity for any two different wavelengths.