Laser resonator with direction sensitive decoupling

A laser source comprising:

• an optical resonator having:
• a polarization dependent coupling device for coupling light having a first state of polarization into a first path, and for coupling light having a state of polarization perpendicular to said first state of polarization into a second path;
• a polarization modifying device;
• and
• a filter,
• wherein said polarization dependent coupling device receives, from a first propagation direction, a light beam having said first state of polarization, and couples said light beam to said polarization modifying device,
• wherein said polarization modifying device modifies a polarization of said light beam, before said light beam reenters said first path from a second propagation direction, in order to couple into said second path a portion of said light beam traveling in said second propagation direction, and
• wherein said filter is arranged in an optical path of said light beam after passing said polarization dependent coupling device in said first propagation direction and before reentering said polarization dependent coupling device in said second propagation direction;
• and
• a laser medium adapted for emitting said light beam,
• wherein said optical resonator receives said light beam from said laser medium to provide an external resonator for said laser medium.

A method for coupling out a portion of a light beam traveling in an optical resonator, comprising:

• receiving, from a first propagation direction, a light beam having a first state of polarization;
• coupling said light beam from said first propagation direction in a first path of a polarization dependent coupling device;
• coupling said light beam through a filter;
• modifying a state of polarization of said light beam;
• reentering said light beam with said modified state of polarization in said first path from a second propagation direction;
• and
• coupling out, from a second path of said polarization dependent coupling device, a portion of said light beam traveling in said second propagation direction, wherein said portion depends on said modified state of polarization,
• wherein said filter is arranged in an optical path of said light beam after passing said polarization dependent coupling device in said first propagation direction and before reentering said polarization dependent coupling device in said second propagation direction.