Ultra-fast and stable method to change the divergence of a laser beam

An optical system, comprising:

• a housing comprising:
• a first lens element having an optical center;
• a second lens element having an optical center spaced apart from the first lens element by 35-55 mm and oriented such that a beam passing through the optical center of said first lens element will also pass through the optical center of the second lens element, the beam defining an optical path;
• and
• at least one planar, optical slab configured to be movable between at least two positions, a first position wherein at least a portion of a planar surface of the optical slab is disposed between the first and second lens elements such that a beam transmitted therethrough also passes through the planar, optical slab and a second position wherein the planar, optical slab is fully outside of the optical path created by the first and second lens elements.

An optical system, comprising:

• a housing comprising:
• a first lens element having an optical center;
• a second lens element having an optical center spaced apart from the first lens element and oriented such that a beam passing through the optical center of said first lens element will also pass through the optical center of the second lens element, the beam defining an optical path;
• and
• a rotatable turret comprising a plurality of planar, optical slabs of different thicknesses, wherein the rotatable turret is configured to rotate each of the plurality of planar, optical slabs between at least two positions, a first position wherein at least a portion of a planar surface of the planar, optical slab is disposed between the first and second lens elements such that a beam transmitted therethrough also passes through the planar, optical slab and a second position
• wherein the planar, optical slab is fully outside of the optical path created by the first and second lens elements,
• wherein the optical system is athermal from −20 C to 60 C.