Terahertz imaging via electrooptic effect request pdf. Here we will discuss on electrooptic pockels and kerr effects. The basic idea behind electrooptic devices is to alter the optical properties of a. First it is studied the anisotropic media in general where is deduced the electro optic tensor and the appropriate indexes ellipsoid expressions to a crystal such as lithium niobate, for a uniaxial media. The four electro optic effects in the order listed here are respectively the analogues of the first four magneto optic effects. We present a complete frequencydomain description of electro optic eo detection of terahertz thz electromagnetic radiation, including a description of the ellipsometry technique employed. In the particular case of the pockels effect, also called linear electro optic effect. The kerr effect is distinct from the pockels effect in that the induced index change is directly proportional to the square of the electric field instead of varying linearly with it. Scrymgeour, alok sharan, and venkatraman gopalana materials research institute and department of materials science and engineering. The electro optic effect consists in the change of the refractive index induced by an electric. Other electrooptic devices use the transverse effect with the light beam perpendicular to the applied field. In reference 7, the overvoltage was captured first by a capacitive voltage divider, then transformed to an optical signal by an electro optic sensor, which solved the insulation problem 7.
As in the case of piezoelectricity, described in the previous chapter, electro optic effects are observed only in materials that are noncentrosymmetric. Midinfrared electrooptic modulation in fewlayer black. It is the equivalent of the kerr electro optic effect. Osa the electrooptic effect in uniaxial crystals of the.
It takes the slow ray longer to traverse the crystal than it takes the fast ray. Integrated electrooptic sensor based transient voltage. The term encompasses a number of distinct phenomena, which can be subdivided into. The electro optic effect has also been used in silicon pn junctions to induce rapid and precise phase shifts, however, this comes at the expense of optical loss, and has poor spectral selectivity. The electrooptic phenomena as described in this book deal entirely with the effect of an electric field on the index of refraction of materials in the solid state. Pdf large electrooptic effect in tensile strained geon. The electrooptic effect is the modification of the refractive index by an externally applied electrostatic field.
Cellulose electrooptic effect oregon state university. A pplyin g an electric field to the crystal in duces a chan ge in the in dices of refraction both ordin ary. In kerr cell modulators, the electro optic effect is a function of the square of the e robert goldstein is president of lasermetrics, inc. An electrooptic effect is a change in the optical properties of a material in response to an electric field that varies slowly compared with the frequency of light. The optical power of a ld is a function of the injection current, and thus a convenient way to convert an electrical signal into an optical signal is through the direct modulation of the injection current. This is the basis of the electro optic display device called the surface. Sumfrequency generation from optically active liquids in the presence of a dc electric field p. The electro optic effect is the change in the refractive index resulting from the application of a dc or lowfrequency electric field fig. The electrooptic effect is the phenomenon that the refractive index of a material can be modified with an electric field. The electrooptic and acoustooptic effects and modulation of light. Mechanism of the electrooptic effect and nonlinear.
The electric field applied to the crystal can alter or induce birefringence by changing the refractive index of the medium. Modeling of straininduced pockels effect in silicon. Transverse effect devices avoid the use of transparent electrodes in the light path. Longitudinal electrooptic modulation using a poled. Some practical applications of the faraday magnetooptic. Onchip dispersion measurement of the quadratic electro.
The method utilizes the electro optic sampling, and we use a chargecoupled device to detect a spatial distribution of the probe beam polarization rotation by the efieldinduced pockels effect in. This effect can occur only in noncentrosymmetric materials. Pdf short peptides made from repeating units of phenylalanine selfassemble into a remarkable variety of micro and nanostructures including tubes. This effect is useful for the production of a large number of optical devices, such as phase modulators, dynamic wave retarders, intensity modulators, scanners, and directional couplers. T he electrooptic am plitude m odulator e o a m is a pockels cell type m odulator con sistin g of tw o m atched lithium n iobate crystals packaged in a com pact housin g w ith an r f in put con n ector. This effect is usually found in colloidal solutions of magnetic particles and as m might be large 0cm is too. Electrooptic modulation is an important functionality in an optical transmitter, which translates electrical signals into the optical domain. The fundamental mechanism for the collisionpressure. Chapter iv other devices electro optic effect electro optic effect can be observed when light propagates through a crystal in the presence of an electric field. Electrooptic control of the superprism effect in photonic.
Longitudinal effect devices are particularly useful for light beams of large crosssectional area. Anomalous electrooptic effect in sr ba nb o single. Electro optic effect, magnetic optic effect, pressure optic effect, molecular beam technique, laser technology, chemical reaction dynamics, collisioninduced optic effect, pressureinduced optic effect 1. You may subscribe either as an osa member, or as an authorized user of your institution. Chapter iv other devices electro optic effect electro. Wise2 1department of chemistry and chemical biology, cornell university, ithaca, new york 14853, usa 2department of applied and engineering physics, cornell university, ithaca, new york 14853, usa. We will look at a certain class of crystals centrosymmetric crystal which will remain unaffected as regards this pockels effect, but will exhibit kerr effect then we will.
Retardation, interference colors in anisotropic crystals, the two rays of light produced by double refraction travel at different velocities through the crystal. Electro optic effect magnetic field eddy current effect perme ability joule effect magneto magneto caloric effect magnet o optic effect stress direct piezo electric effect villary effect elastic modulus thermomechanical effect photo elastic effect heat pyro electric effect thermo magne tization thermal expansion. Monolithic lithium niobate photonic circuits for kerr. The kerr cell, also referred to as a kerr electrooptical shutter, is a device employing the kerr effect to interrupt a beam of light up to 10 1 0 times per second. Electrooptic materials and applications springerlink. Pdf strong electrooptic effect and spontaneous domain.
The goal of this thesis is to reevaluate both tengman and attenuated total reflection atr methods for measuring the linear electrooptic eo coefficients of poled organic thin films based on a multilayer structure containing a transparent conducting oxide tco layer. The nonlinear optical properties and electrooptic effects of some. Propagation of electromagnetic waves in anisotropic media. In the linear electrooptic effect, the size of the perturbation to the refractive index is directly proportional to the strength of the local electrostatic field. Photocurrent transients, photoluminescence, electroluminescence, quasi. Characterization of linear electrooptic effect of poled. Reflection mode the second category of magneto optic effects deals with reflected light from the surface of a magnetized material. Another practical measuring method is based on the electro optic effect. Electro optic control of the superprism effect in photonic crystals david scrymgeour, natalia malkova, sungwon kim, and venkatraman gopalana materials research institute and department of materials science and engineering, pennsylvania state university, university park, pennsylvania 16802 received 17 january 2003. Owing to the applied electric field, there is the universal kerr effect. Some practical applications of the faraday magneto optic effect, the kerr electro optic effect, and the pockels electro optic effect in the early decades of the 20th century. Request pdf large secondharmonic generation and linear electrooptic effect in trigonal selenium and tellurium trigonal selenium and tellurium crystalize in helical chainlike structures and.
In many linear electrooptic devices the longitudinal effect is used, that is, the light beam and electric field are parallel. Electro optic modulation has been first demonstrated using a poled electro optic polymer films, placed in a fabryperot cavity. The kerr effect, also called the quadratic electrooptic effect, is a change in the refractive index of a material in response to an applied electric field. In our configuration, incorporating an electro optic material in the spacer layer of a fabryperot device creates such a structure whose optical transmission characteristics depend on. Rp photonics encyclopedia electrooptic effect, pockels. The pockels effect first described in 1906 by the german physicist friedrich pockels is the linear electro optic effect, where the refractive index of a medium is modified in proportion to the applied electric field strength. All materials show a kerr effect, but certain liquids display it more strongly than others. The electrooptic effect is the change in the response of a material to light when that material is subjected to an electric field. A large number of applications in everyday life depend on the electrooptic effect. Electrooptic properties of kh 2 po 4 and isomorphs, kdp, kdp dkdp, adp, adp table of material properties appears below the pockels electro optic effect crystals which belong to twenty symmetry classes which lack a center of symmetry can show a linear electro optic effect, that is, a change in refractive indices directly proportional to. The electro optic effect in uniaxial crystals of the type x h 2 po 4. These frequencydomain results show the effect of eo detection of a pulse of thz radiation as the product of three spectral filters acting on the complex amplitude spectrum of the thz pulse that is. Electrooptic properties of kh and isomorphs, kdp, kdp. Introduction the interaction between the light and matter has.
Large secondharmonic generation and linear electrooptic. While those sensors mentioned above each has several drawbacks. Linearly polarized light light vibrating in one plane, as shown in the figure is passed through a liquid, such as nitrobenzene, contained in a cell with transparent walls. The field dependence of absorption in the ge films was measured from. The effect has been characterized in a wide range of materials, including inorganic crystals mostly ferroelectric compounds, organic and molecular crystals, and crystalline and noncrystalline. Propagation of weak optic signals in strong quasistatic fields description using renormalized linear parameters. The kerr effect is similar to the pockels effect except that the field is applied perpendicular transversely to the incident light, as shown in figure 1b, and a liquid medium is used rather than a crystal. Rp photonics encyclopedia pockels effect, electrooptic. Request pdf electrooptics the electrooptic effect is the modification of the refractive index of a material crystal or glass, caused by an. John kerr, scottish physicist 1824 1907 nonlinear in optical effects.
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