Abstract: A differential polarization interferometer is provided. An interferometer performs direct measurement of phase shift of a light wave passed under an arbitrary angle through a sample composed of a transparent substrate holding a thin deposited test film, for metamaterial testing. An example apparatus has a laser source and a first polarizer, and two optically connected arms. A first arm creates orthogonally polarized components of a single output beam for a broadband non-polarizing beam splitter. A second arm has a controllable phase retarder to introduce a phase shift into one polarization component of the reflected single output beam, and a second polarizer to equalize and mix the polarization components of the reflected single output beam. This transforms the reflected single output beam into a beam resulting from interference of polarization components of the reflected single output beam. A photodetector transforms an intensity of the beam into an electric signal for output.

Abstract: A light pen for writing on a polarized light sensitive surface is disclosed. Light emitting diodes emit non-polarized light and a polarization block comprising of a truncated cone shaped collimating optical element, a broad band polarization divider, a broadband semi-wave plate, shifting bi-prism and light beam coupler are built to convert the non-polarized light to be converted to polarized uniform intensity light that is focused using a set of projection lens to a writing surface. The said light pen can be used for creating non erasable writing on many types of articles, documents, and records that would provide verification of authenticity and security.

Abstract: A differential polarization interferometer is provided. An interferometer performs direct measurement of phase shift of a light wave passed under an arbitrary angle through a sample composed of a transparent substrate holding a thin deposited test film, for metamaterial testing. An example apparatus has a laser source and a first polarizer, and two optically connected arms. A first arm creates orthogonally polarized components of a single output beam for a broadband non-polarizing beam splitter. A second arm has a controllable phase retarder to introduce a phase shift into one polarization component of the reflected single output beam, and a second polarizer to equalize and mix the polarization components of the reflected single output beam. This transforms the reflected single output beam into a beam resulting from interference of polarization components of the reflected single output beam. A photodetector transforms an intensity of the beam into an electric signal for output.

Abstract: A light pen for writing on a polarized light sensitive surface is disclosed. Light emitting diodes emit non-polarized light and a polarization block comprising of a truncated cone shaped collimating optical element, a broad band polarization divider, a broadband semi-wave plate, shifting bi-prism and light beam coupler are built to convert the non-polarized light to be converted to polarized uniform intensity light that is focused using a set of projection lens to a writing surface. The said light pen can be used for creating non erasable writing on many types of articles, documents, and records that would provide verification of authenticity and security.