Publisher Summary This chapter focuses on the concept of elastooptic light modulation and deflection It deals briefly with the tensor properties of elastooptic effect and discusses some materials useful for application in devices The chapter discusses some aspects common to all elastooptic devices and the fundamental limitations of refractive and birefringent approaches In addition, it discusses diffractive deflectors and modulators and their design, limitations, and technological problems Elastooptic devices also benefit from the larger category of materials with useful effects available, compared with electrooptic ones There linear effects are only found in crystal classes that lack a center of symmetry, and thus are also piezoelectric Spurious elastooptic effects generated by the driving electric field, thus, need special attention Also, the larger class of available materials makes it easier to circumvent problems arising from optical damage and inhomogeneity

VI Elastooptic Light Modulation and Deflection

Quantitative bounds for the normalized second moment of a random signal process are expressed in terms of the statistics of measured quantities. No weighting is used, and, essentially, the only assumption made on the signal process is that its spectrum be bandlimited.

Estimation of Spectral Moments without Weighting

Excitation of an ultrasonic light modulator by random electrical signals will cause a random modulation to be imposed on the emerging light wavefront. A general solution for the resulting light diffraction patterns is obtained, from which the conditions are determined for which the diffracted light‐intensity distribution will be a valid representation of the power spectral density of the input electrical noise signal. The necessary experimental conditions for which the variance of the spectral measurements will be small are determined. The percentage of the light‐modulator bandwidth over which measurements will be valid is found to be dependent on the product of the spatial‐frequency bandwidth of the light modulator and the length of the optical aperture; this effect is evaluated and numerical results are presented. The case in which the input to the ultrasonic light modulator consists of a deterministic signal and noise is also considered. Using these results, the diffracted light levels due to signal an...

John B. Minkoff

Papers

Operation of Ultrasonic Light Modulators under Conditions of Random Electrical Excitation