We present the design and fabrication of a multicomponent optical system for LiDAR applications. The system comprises four stages: a commercial cylindrical lens, a custom freeform trilobe lens, a set of three custom reflective diffraction gratings, and a custom monolithic array of nine freeform mirrors. This optical set-up is coupled to an on-chip linear Optical Phase Array (OPA): the combination of linear beam steering provided by the OPA, and orthogonal linear steering achieved by the diffraction gratings results in a beam scan over nine directions in 3D. All the custom components have been designed and fabricated at VUB B-PHOT’s Photonics Innovation Center.
We present an example of design, tolerancing and fabrication of freeform plastic lightguides for optical sensing applications. The design of the lightguides relies on Nonimaging Optics principles and uses raytracing simulations for analysis and optimization. We examine the influence of fabrication parameters on the simulated performance and show ways to minimize their impact. The presented lightguides have been fabricated at the Photonics Innovation Center of VUB – B-PHOT.
Earth observation and greenhouse gas sensing from space provides vital information for climate and climate change monitoring, indicating the importance of novel spaceborne telescopes and spectrometers. We present a novel freeform pushbroom imaging spectrometer enabling the sensing of water vapor, carbon dioxide and methane in the atmosphere, while fitting within 2 CubeSats Units. The design comprises a 2-mirror freeform telescope, combined with a near-infrared (1100 – 1700 nm) spectrometer featuring 3 freeform mirrors and a reflective grating, providing both spatial and spectral information using a 2D detector. All mirrors are described and optimized using XY polynomials, enabling a nearly diffraction-limited performance. The novel design is exceeding the state-of-the-art, by showing a full FOV of 120°, a spatial resolution of 2.6 km, and a spectral resolution of 13 nm. According to our knowledge, our novel design shows the widest field-of-view that has ever been realized for space-based telescopes, nearly reaching Earth observation from limb to limb from an altitude of about 700 km. The freeform telescope mirrors were manufactured in-house using high-precision 5-axis milling and 5-axis ultraprecision diamond tooling. Finally, a laboratory proof-of-concept demonstrator was realized validating the field-of-view and focusing spot sizes, paving the way for future space missions that target wide field-ofview imaging and/or an enhanced climate monitoring.
Wide field-of-view imaging optics offers a huge potential for space-based Earth observation and climate change monitoring by capturing global data. We present the design and proof-of-concept demonstration of a freeform 2-mirror space-based telescope featuring a full field-of-view of 120°, nearly reaching Earth observation from limb to limb from a nominal altitude of 700 km, while showing a spatial resolution of 2.6 km, and fitting within 1 CubeSat unit. Our design benefits from freeform optics to maximize the field-of-view, while maintaining a diffraction-limited image quality and minimizing the system dimensions. Particularly, both mirror surfaces were accurately modelled and optimized using an XY polynomial description. Subsequently, the mirrors are manufactured using high-precision 5-axis milling and ultraprecision diamond tooling, after which a laboratory demonstrator setup of the telescope was realized. We believe this design paves the way towards future space missions enabling an improved Earth observation, leading to an enhanced monitoring of climate and climate change.
We present a miniature freeform lightguide for sensing applications, designed according to the principles of the flow-line method from Nonimaging Optics. The optic is obtained by combining two 2D flow-line concentrators in a curved monolithic piece, achieving 45° half-acceptance angle and 40° beam steering in a very compact volume (about 1.3 x 2.0 x 20 mm3). We show how the initial design has been adjusted after a thorough tolerance analysis and describe its fabrication through plastic injection molding. The design of the mold involves a non-standard 3D-puzzle approach, which allows uniform high optical quality and minimizes the fillet radius on the optic.
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