Enhancing the sensitivity of an adaptive holographic interferometer using non-Bragg diffraction orders

Abstract

The signal-to-noise ratio of the output of an adaptive holographic interferometer (AHI) based on a Bi(12)TiO(20) crystal is investigated. We show experimentally that the sensitivity of an AHI using the non-Bragg orders of diffraction in a thin photorefractive material is more than an order of magnitude greater than that of an AHI employing two-wave mixing in photorefractive volume holograms.

Adaptive Holography in Liquid Crystal Light-Valves

“…Indeed, if $\rho \ll 1$ and for $m=-1$ we have ${\hat{P}}_m\propto J_0\left(2k_0\epsilon \right)J_1\left(2k_0\epsilon \right)$ which has a maximum at $1.1$ $rad$. As already done in other AHI setups [38,39], this property has been used to find the relation between the displacement ε and the measured lock-in voltage $V_{lock-in}$.…”

“…After the seminal paper of Petrov on adaptive holographic interferometry (AHI) [4], the possibility of using the dynamic holographic recording technique to achieve highly precise measurements of small displacements has been demonstrated in numerous systems [5]. Since then, AHI has been proved as a useful tool for measuring small vibration amplitudes of reflecting objects [6,7,8,9]. A similar technique has been recently employed to realize acousto-optic imaging [10].…”

Nonlinear holography for acoustic wave detection

“…2,3 There, adaptive holography interferometry (AHI) had been proved as a useful tool for measuring small vibration amplitudes of reflecting objects, see, e.g., Refs. [4][5][6][7][8] and the articles cited therein. More recently, a similar technique has been employed to realize acousto-optic imaging through highly scattering biological media.…”

Self-adaptive vibrometry with CMOS-LCOS digital holography

“…Successively implemented in photorefractive materials, it had been proved as a useful tool for measuring very small vibration amplitudes of 3D objects with a scattering surface [12][13][14][15]. More recently, it has been employed to realize acousto-optic imaging through highly scattering biological media [16] and to achieve the detection of picometer displacements by using light valves [17].…”

“…Another advantage is offered by the possibility of using a spatial transformation in order to optimize the diffraction efficiency, for example, by introducing an asymmetric grating profile. [17] or photorefractive crystals [13]). Black squares: experimental points; continuous line: theoretical prediction.…”