FOLDED RESONATOR WHICH IS INSENSITIVE TO MISALIGNMENT

摘要

A laser comprising a standing wave resonator comprises a first resonator section (26), which has the first end mirror (24, 24') and, if appropriate, others of the optical elements (32, 40), which interact with the laser beam between the first end mirror (24, 24') and the laser medium (23) and a second resonator section (27), which has the second end mirror (25) and others of the optical elements (36 - 39), which interact with the laser beam between the laser medium (23) and the second end mirror (25). At least one of the optical elements (24, 40) of the first resonator section (26) is embodied in focusing fashion. As a result, the beam axes (30, 30') of the laser beam which arrives upon respective tiltings of at least one of the optical elements (25, 36-39) arranged in the second resonator section (27) have at least one crossing point (31). Said crossing point (31) or one of said crossing points (31) of the beam axes (30, 30') of the laser beam lies in the pump region of the laser medium (23) or is at a distance from the pump region which amounts to less than the Rayleigh length. The radius (w) of the laser beam, at least over the section of the laser beam which lies between the laser medium (23) and the closest focusing element (24, 40) of the first resonator section (26), is less than five times, preferably less than three times, the radius (w) of the laser beam in the pump region of the laser medium (23).