Optical waveplates

Kgure 15.27. Temperature profile, induced tensile stress, and generated retardation of poly(amic acid) film fixed and cured in a metal frame. 

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This chapter describes the synthesis of partially fluorinated polyimides for optical teleconununications applications," " 2 their optical transparency (optical loss), refractive index, and birefringence properties" in addition to their fundamental properties. It also describes their device application as optical interference filters," " optical waveplates," and optical waveguides." -" ... 

We anticipate that, regardless of the detuning from an optical resonance used, the parameters f, g, and h will always be determinable from measurements of SHG as a function of the rotation angle of a quarter waveplate used to set the polarization state of the incident fundamental light. The amount of SHG-CD can be calculated from the parameters or, of course, read directly... 

Calcite and quartz are commonly used for optical polarization components, such as waveplates, polarizers, and beam splitters. Such inorganic crystals have... 

A. M. Title, Improvement of birefringent filters. II Achromatic waveplates, Applied Optics, 14, 229 (1975). 

Figure 15.26. Schematic representation of the function of a half-waveplate. It rotates the polarization direction of optical signals by 90°.

Matsuda and Ando [34] discuss the control of molecular orientation and anisotropic optical properties of uniaxially drawn fluorinated PI films based on pyromellitic dianhydride and 2,2 - fs-(trifluoromethyl)-4,4 -diaminobiphenyl used for light wave circuit applications. Methods of controlling in-plane birefringence in PI films were developed and a PI waveplate was prepared. This waveplate was inserted into a groove formed in an arrayed waveguide grating, the polarisation dependence of which was completely eliminated. 

A typical design of a reflective optical circulator is shown in Fig. 18, where a 90-degree polarization reflector, consisting of a quarter-waveplate and a mirror, is used for... 

Optically transparent Pis are also of special importance for optoelectronic devices such as optical waveguides for communication interconnects and optical half-waveplates for planar lightwave circuits. 

This matrix now allows us to propagate coherent light through an arbitrarily oriented birefringent material. We can also define useful retardation elements such as half and quarter waveplates, which can be used to make up functional optical systems. A combination of these elements can also be analyzed from right to left as a series of matrix multiplications. 

A further interesting use of the focal-conic to homeotropic texture transition is in infrared modulation [272]. Here it was found possible to modulate infrared light at A=8-12 pm with a maximum transmission of 87%, a contrast of 93%, and turn on and off times of 1 ms and 125 ms, respectively. A further window examined was 3-5 pm, and this work suggests that other chiral nematic electrooptic effects could be exploited in the near infrared. In communications technology a 2x2 optical switch for fiber-optics has been developed [273] using a chiral nematic film and two switchable nematic waveplates. It has been demonstrated that this is suitable for LED or laser sources. The device worked at 1.318 pm and had switching times of 40 ms with -26 dB crosstalk between unselected fibers. There will clearly be further advances in this use of the unique optical properites of chiral nematics. 

Birefringent components are used for optical polarization devices such as polarizers, waveplates, and beam splitters. Birefringence means that the refractive index of materials is different in different directions. The refiactive index of a material is related to the molecular polarizability via the Lorentz-Lorenz equation as follows ... 

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