Highly efficient broadband polarization retarders and tunable polarization filters made of composite stacks of ordinary wave plates

Efficient broadband polarization retarder via shortcuts to adiabaticity

The use of two-level atomic systems in quantum optics allows for the design of highly efficient and broadband achromatic retarders through the application of adiabatic passage and composite pulse techniques. In this work, we propose shortcuts to adiabaticity to improve broadband polarization retarders with shorter lengths. We achieve this by inversely engineering the relative refractive indices and further optimizing them with respect to the perturbation of input wavelength. Our results are compared with adiabatic and composite protocols, demonstrating that our method provides the advantage of integrating efficiency and robustness.

Composite polarization systems for independent controlling polarization of two beams with different wavelengths

The usage of independent and simultaneous control of the state of light polarization at different wavelengths can expand the capabilities of polarization methods for biomedical application. Unfortunately, all known methods of polarization conversion cannot convert the state of light polarization at different wavelengths independently. We propose a method and device for independent and simultaneous control of the polarization state at two wavelengths. We have theoretically proved the possibility of maintaining the phase shift at the first wavelength unchanged while simultaneously and independently changing the phase shift at the second wavelength from 0 to 180 degrees. The capabilities of the method were for the first time demonstrated for radiation with wavelengths λ = 632.8 nm and λ = 488 nm. At the wavelength λ = 632.8 nm, the phase shift remained equal to 180° whereas at the wavelength λ = 488 nm, it varied in the range from 121° to 136°.

Individual selective rotation of the linear polarization of single light beam in a bundle

An approach for aligning of linear polarized light beams with different wavelengths into a single beam with parallel linear polarization is presented and experimentally demonstrated. The main idea is based on the application of recently developed composite half-wave plates, working as linear polarization filters.