What Happens When Two Lasers Collide

Can two lasers interfere?

Interference from two beams of different sources are possible, if they have same wavelength. Interference always occurs even if the wavelengths are different. However, interference between two beams of different wavelength results in a traveling interference pattern.

Can lasers be combined?

When combining laser beams together into a collinear path, dichroic filters, also known as dichroic beamsplitters or dichroic mirrors are typically used. Dichroic filters separate the incoming spectrum and transmit one wavelength region, while reflecting another.