Silicon acousto-optic modulator

Abstract

An acousto-optic modulator includes a (100), (010) or (001) single crystal silicon acousto-optic interaction medium, and at least one transducer for emitting an acoustic wave attached to the single crystal. The transducer has a first electrode layer disposed on one side and a second electrode layer disposed on its other side. The transducer is aligned to the single crystal so that the direction of acoustic propagation in the silicon crystal is substantially along the (100), (010) or (001) direction. A q-switched laser includes a modulator according to the invention.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

A fuller understanding of the present invention and the features and benefits thereof will be accomplished upon review of the following detailed description together with the accompanying drawings, in which:

FIG. 1( a) is a schematic showing a modulator device with input and output (diffracted) beams, and associated k-vector diagram, while FIG. 1(b) shows the associated k-vector diagram in more detail.

FIG. 2 is a schematic of an exemplary silicon Q-switch according to the invention, showing transducer, acoustic wedge (to frustrate reflection of acoustic energy back into transducer), and definitions of the various relevant dimensional parameters.

FIG. 3( a) shows a slice through slowness surface for silicon in the plane containing the (110) and (001) directions. Arrows represent particle displacement vectors, in-plane component is drawn outside, out of plane component is drawn inside. Inner curve represents the longitudinal mode.

FIG. 3( b) shows a slice through slowness surface for silicon in the plane containing the (100) and (010) directions.

FIG. 4( a) shows a slice through slowness surface for silicon in the plane containing the (100) and (001) directions. Arrows represent particle displacement vectors, in-plane component is drawn outside, out of plane component is drawn inside.

FIG. 4( b) shows a slice through slowness surface for silicon in the plane containing the (100) and (010) directions. FIGS. 4a and 4b are identical because of the cubic symmetry of silicon.

FIG. 5 shows one possible realization of a polarization insensitive acousto-optic modulator according to the invention. In one region, both acoustic waves are present, propagating orthogonal to one another.

FIG. 6 shows a pulsed q-switched laser according to an embodiment of the invention.

Claims

1. An acousto-optic modulator, comprising: a (100), (010) or (001) single crystal silicon acousto-optic interaction medium, andat least one transducer for emitting an acoustic wave attached to said single crystal, said transducer having a first electrode layer disposed on one side of said transducer and a second electrode layer disposed on the other side of said transducer, wherein said transducer is aligned to said single crystal so that the direction of acoustic propagation in said silicon crystal is along the (100), (010) or (001) direction.

2. The modulator of claim 1, further comprising Brewster angled end faces at at least one of an optical input or an optical output of said modulator.

3. The modulator of claim 2, wherein said at least one transducer comprises at least a first and a second transducer, said first and second transducer mounted orthogonally to each other on said silicon crystal.

4. A Q-switched laser, comprising: a resonator cavity comprising a high reflecting back mirror;a partially reflecting output coupler,an amplifying laser material between said back mirror and said output coupler, andan acousto-optic modulator disposed on either side of said amplifying material between said back mirror and said output coupler, said modulator comprising a single crystal silicon acousto-optic interaction medium, and at least one transducer for emitting an acoustic wave disposed on said substrate, said transducer having a first electrode later disposed on one side of said transducer and a second electrode layer disposed on the other side of said transducer, wherein said silicon crystal is cut and said transducer is aligned to said single crystal so that the direction of acoustic propagation in said silicon crystal is along the (100), (010) or (001) direction.

5. The laser of claim 4, wherein all components of said laser are directly bound together.

6. The laser of claim 4, further comprising Brewster angled end faces at at least one of an optical input or an optical output of said laser.

7. The laser of claim 4, wherein said at least one transducer comprises at least a first and a second transducer, said first and second transducer mounted orthogonally to each other on said silicon crystal.

8. The laser of claim 4, wherein said amplifying laser material comprises Er3+-YAG.