Transmissive diffractive membrane optic for large aperture lightweight optical telescope

Abstract

Transmissive diffractive membrane optic can be used in space optical telescope to reduce the size and mass of imaging system. Based on the international research results about transmissive diffractive membrane, a 4-level diffractive substrate with 100mm apertures was designed and transmissive diffractive membrane was fabricated by spin coating. High-precision support structure for diffractive membrane with surface precision 0.12λ RMS (λ=632.8nm) was introduced, and that can meet the diffractive imaging requirements. Diffraction efficiency of the diffractive membrane supported by support structure was tested, and the test results showed that diffraction efficiency was >50%. The step figure test results illustrated the etched deep precision was less the 10nm. The imaging wavefront test result demonstrated a wavefront error of about 38 nm RMS. The transmissive diffractive membrane optic can be very useful for large aperture imaging system to realize low mass and low cost.

Effect of Wet Expansion Behavior on Polyimide Membrane Diffractive Lens

“…Then we can derive a relationship between m 2 and m 1 in Equation (10). α and β are used for simplification.…”

“…Wave-front error is the key parameter in evaluating the imaging quality of FZLs. The wave-front error of PI membrane, FZL, is theoretically influenced by substrate wave-front error and fabrication errors [9][10][11][12]. The key fabrication error for PI membrane FZL is structure position error (∆r m ), as shown in Figure 1 [13][14][15].…”

A High-Precision Real-Time Pose Measurement Method for the Primary Lens of Large Aperture Space Telescope Based on Laser Ranging

“…Theoretically, it overturns the traditional imaging systems, which rely on the primary lens with a curved surface. Technically, it breaks through the bottleneck of increasing the aperture, such as telescope weight, tolerance control of primary lens surface, and envelope size of primary lens [ 3 , 4 ]. Similar projects, such as the Membrane Optic Imager Real-Time Exploitation (MOIRE) program supported by US Defense Advanced Research Projects Agency (DARPA) [ 5 , 6 , 7 , 8 ], have been called the 21st-century space disruptive imaging technology.…”