An optical component for illuminating a sample region with a periodic light pattern comprises: a first waveguide, a further waveguide and an optical splitter. The optical splitter has an input for receiving light, a first output and a second output. The first waveguide is optically coupled to the first output, to direct the first input light into the sample region in a first direction. The second output is optically coupled to the sample region to direct second input light into the sample region in a second direction. The further waveguide is arranged to receive third input light which is directed into the sample region in a third direction. The first direction, second direction and third direction are different from one another. The first and second input light interferes to form a periodic pattern in the sample region. The optical component may be used for structured illumination microscopy.

An optical component for illuminating a sample region with a periodic light pattern comprises: a first waveguide, a further waveguide and an optical splitter. The optical splitter has an input for receiving light, a first output and a second output. The first waveguide is optically coupled to the first output, to direct the first input light into the sample region in a first direction. The second output is optically coupled to the sample region to direct second input light into the sample region in a second direction. The further waveguide is arranged to receive third input light which is directed into the sample region in a third direction. The first direction, second direction and third direction are different from one another. The first and second input light interferes to form a periodic pattern in the sample region. The optical component may be used for structured illumination microscopy.

Provided is a handheld device and a method for detecting weld defects on a weld surface. The handheld device projects a thin beam laser light on the weld surface using a laser emitter. A processor receives the projected thin beam laser light from a laser receiving sensor, which indicates captured contours of the weld surface. The captured contours are processed to filter laser lines and extract contours. The extracted contours are utilized to classify a type of weld surface such as, surface joints, butt joints, corner joints, and tee joints. The processor, upon classifying, automatically adjusts angle and position of the laser light to be projected on the weld surface and detects deviation patterns by employing an ensemble of a laser line extraction process and a pixel width measurement process. The processor determines the detected deviation patterns as one or more defects on the weld surface that is being inspected.