APOLLO Laser

The laser used for APOLLO is a commercial, product-line laser called the Continuum Leopard. Its basic properties are:

• 532 nm wavelength (green)
• <100 ps pulse width
• 115 mJ per pulse
• 20 Hz repetition rate (yielding 2.3 W average power)
• 9 mm output beam size, M²=2.5
• 2×4×1.2 cubic foot volume (laser bench itself)
• 2.5% RMS pulse energy stability

Laser Bench

Plan View

Laser Guts

Output End

Electronics Racks

The laser beam is expanded to fill the full aperture of the 3.5 meter Apache Point telescope. The beam quality is such that the atmospheric turbulence ("seeing") is the limiting factor in overall beam divergence enroute to the moon. Typical seeing at Apache Point is 1.0 arcseconds, translating to a 1.8 km diameter footprint at the distance of the moon.

The laser bench is oversized (3×4 ft²), allowing our receiver optics to occupy a spot on the same rigid structure. This bench is mounted onto the back port of the telescope (a bent Cassegrain focus), and enclosed in a temperature-controlled box to keep the laser at its desired operating temperature.

APOLLO Apparatus Page

APOLLO Main Page