Subwave RetarderOffering a building block for optical on-a-chip integration, the Subwave Retarder wave plates fabricated by NanoOpto Corp. of Somerset, N.J., are passive optical components that provide precise phase retardation with less dependence on wavelength, temperature and incidence angle than conventional devices do. When produced using the company's nanopattern transfer and semiconductor processing techniques, the components achieve zero-order retardance that can be specified to any value. The wave plate nanostructures are suitable for the UV to the IR wavelengths and can be applied to arbitrary substrates to facilitate integration into existing optical systems. The components consist of nanometer-scale grating structures patterned on an optical substrate. Optical specifications such as retardance and design wavelength can be customized by controlling the grating height, width and period. The grating period is much smaller than the wavelength. The phenomenon of "form birefringence" causes the nanostructure grating to function as a precision retarder with well-defined and controlled birefringence. A key characteristic of the wave plate is its ability to realize precise retardance values for short wavelengths. Unlike conventional retarders, it can be manufactured for very short wavelengths by altering the design of the grating. The temperature stability, wavelength insensitivity and large field of view of long-wavelength systems can now be achieved in blue and UV applications. The compact devices can be incorporated with optical components such as waveguides and thin-film coatings, enabling applications such as projection displays, CD/DVD devices, laser systems, metrology instruments, astronomy and telecommunications.