Solid-state laser resonators with diffractive optic thermal aberration correction

In high power solid state lasers, thermal lens effect always give rise to the multi-modes oscillation in the resonator. The beam quality will deteriorate with the increase of output power. In this paper, an intra-cavity beam shaper is introduced to actively compensate the thermal lens in the laser resonator. One round trip ABCD matrix of the resonator with an intra-cavity beam shaper and thermal lens is calculated. The design parameters with wide stable zone are concluded through the ABCD matrix. The mode size and stability diagram of the resonator are calculated under different focal length of the thermal lens. The relationship between the adjustment of the intra-cavity beam shaper and the mode size under different thermal lenses are concluded, and general method to actively control the modes contents by adjusting the intra-cavity beam shaper is introduced. The effectiveness and performance of active mode control with the intra-cavity beam shaper are verified by simulations of the output modes of resonators. It shows that the M 2 factor is well maintained below 1.6 even the focal length of the thermal lens changes from 5m to 0.5m.

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“…In the active mode calculations, the product of small signal gain and gain length is g 0 L g =10, Is=1000W/cm 2 …”

Section: Simulation Results Of Thermal Lens Compensationmentioning

confidence: 99%

Active mode control of solid state laser using an intra-cavity beam shaper

et al. 2015

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“…Aspheric laser-cavity optics have been demonstrated to perform many advanced functions such as mode shaping, 2,3 singlemode selection, 4 and thermal-aberration correction. 5 Many aspheric optics for laser applications have been fabricated as diffractive elements whose phase is a 2-wrapped version of the desired profile ͑or a -wrapped version in the case of diffractive mirrors, because the light travels through an element twice on reflection͒. Due to the phase discontinuity and fabrication errors, a laser resonator with diffractive elements is very susceptible to scattering noise.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of large-sag aspheric micro-optics with nanometer accuracy using electron-beam lithography on curved substrates

Yang

Leger

2006

Opt. Eng

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Smooth patterns were written into PMGI electron-beam resist using electron-beam lithography on BK7 blank concave mirror substrates, resulting in aspheric optics with sag as large as 4 m. Interference microscope measurements revealed that the fabricated optics had height accuracy of 10 nm. These optics were designed for flattop mode shaping in laser resonators. Excellent performance of these optics has been demonstrated by testing them as fixed phase-conjugate mirrors outside laser resonators, as well as mode-shaping mirrors within laser resonators.

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“…First, this is done for tailoring the spatial intensity distribution of the fundamental mode [1±4] and, second, for thermal aberration correction in solid-state lasers [5,6]. Third, a DOE inside the laser is used for the enhancement of the transverse mode discrimination of the cavity [7,8].…”

Section: Introductionmentioning

confidence: 99%