Wollaston prisms are key components for various optical systems such as differential interference contrast (DIC) microscopes, ellipsometers and interferometers. The conventional Wollaston prism consists of two calcite wedges with orthogonal optical axes cemented together (see Fig. 4, left side). The prism splits the incident light beam into two orthogonally polarized beams with a certain shear angle. We propose to use SPhotonix unique femtosecond laser writing technology to fabricate Wollaston prisms in a monolithic fused silica glass. The shear angle can be determined by the retardance gradient across the beam (vertical to the beam propagation direction) created by a birefringent layer with a gradually changing thickness inside the glass (see retardance profile in Fig. 5). This approach allows us to separate two orthogonal polarizations (Fig. 4 right side) and to fabricate efficient Wollaston prisms with a wide range of shear angles, including those required for various optical devices such as DIC microscopes, polarization analyzers and spectrometers. Our prisms have been tested in DIC microscopes showing an excellent performance (Fig. 6).