High-order laser guide star performance for the Euro50 telescope

Area of Science:

• Astronomy and Astrophysics
• Optical Engineering

Background:

• Adaptive optics systems are crucial for high-resolution astronomical observations.
• Laser guide stars (LGSs) are essential for correcting atmospheric turbulence in large telescopes.

Purpose of the Study:

• To analyze the performance of high-order laser guide stars for the future Euro50 telescope.
• To quantify residual errors caused by focus anisoplanatism using multiple LGSs.
• To investigate the impact of pulsed laser power on wavefront measurement accuracy.

Main Methods:

• Numerical simulations were performed to model LGS performance.
• Calculations were conducted for annual mean conditions at the La Palma site.
• The dependence of wavefront measurement error on pulsed laser power was analyzed.

Main Results:

• A Strehl ratio of 0.72–0.82 at 2.2 microm is achievable with 13 LGSs, considering only focus anisoplanatism.
• A Strehl ratio of 0.60–0.70 at 1.25 microm is achievable with 21 LGSs.
• Wavefront measurement error variance remains below 0.2 rad² for laser powers exceeding 14 W.

Conclusions:

• High-order LGS systems are viable for the Euro50 telescope, significantly improving image quality.
• Optimizing the number and configuration of LGSs is critical for achieving desired performance at different wavelengths.
• Sufficient pulsed laser power is necessary to minimize wavefront measurement errors for effective adaptive optics correction.