MCAO for Gemini South

The multi-conjugate adaptive optics (MCAO) system design for the Gemini-South 8-meter telescope will provide near-diffraction-limited, highly uniform atmospheric turbulence compensation at near-infrared wavelengths over a 2 arc minute diameter field-of-view. The design includes three deformable mirrors optically conjugate to ranges of 0, 4.5, and 9.0 kilometers with 349, 468, and 208 actuators, five 10-Watt-class sodium laser guide stars (LGSs) projected from a laser launch telescope located behind the Gemini secondary mirror, five Shack-Hartmann LGS wavefront sensors of order 16 by 16, and three tip/tilt natural guide star (NGS) wavefront sensors to measure tip/tilt and tilt anisoplanatism wavefront errors. The WFS sampling rate is 800 Hz. This paper provides a brief overview of sample science applications and performance estimates for the Gemini South MCAO system, together with a summary of the performance requirements and/or design status of the principal subsystems. These include the adaptive optics module (AOM), the laser system (LS), the beam transfer optics (BTO) and laser launch telescope (LLT), the real time control (RTC) system, and the aircraft safety system (SALSA)

High-harmonic generation: Ultrafast lasers yield X-rays

Table-top sources that generate both extreme ultraviolet light and soft X-rays through high-harmonic generation of ultrafast infrared laser pulses look set to perform tasks previously accessible using only large-scale synchrotrons

Tunable efficient CW ultraviolet generation in periodically poled lithium niobate

Tunable continuous wave single frequency lasers suit to applications in high resolution spectroscopy and metrology. In the given infrared second harmonic generation, efficiency is optimized by using a nonlinear material capable of non critical phase matching. Deviations from the predicted phase matched wavelengths have been measured and used to provide corrections to Sellmeir coefficients at short wavelengths. Photorefractive effects observed at all the UV wavelengths can be eliminated by heating the PPLN crystal above a critical temperature. Reduction in SHG efficiency at shorter wavelengths is attributed to UV absorption

Multiconjugate adaptive optics for Gemini-South

NRC publication: Ye