An official website of the United States government
An approach to designing multiconfiguration afocal telescopes is developed and demonstrated. Freeform surfaces are used to maximize the achievable diffraction-limited zoom ratio while staying in a compact volume for a two-position multiconfiguration afocal optical system. The limitations of these systems with three-mirror beam paths are discussed and subsequently overcome by introducing an additional degree of freedom. In a four-mirror beam path system, the goal of a 5x zoom ratio is achieved with a compensated exit pupil and diffraction-limited performance. A significant benefit in optical performance when using freeform surfaces is shown compared to more conventional surface types.
more »
« less
Exit pupil quality analysis and optimization in freeform afocal telescope systems
Afocal telescopes are often used as foreoptics to existing imaging systems to allow for application flexibility. To properly combine an afocal telescope with an existing imaging system, the exit pupil of the afocal telescope and the entrance pupil of the imaging system must be coincident. Additionally, the exit pupil of the afocal telescope must be well-formed; that is, it must be the correct size and shape to mitigate pupil-matching challenges. This work introduces processes for designing freeform afocal telescopes with an emphasis on understanding how to analyze and control the exit pupil quality of such systems. The included 3-mirror design examples demonstrate the advantages of using freeform surfaces in afocal systems and quantify the tradeoffs required to improve the exit pupil quality.
more »
« less
- PAR ID:
- 10430971
- Publisher / Repository:
- Optical Society of America
- Date Published:
- Journal Name:
- Optics Express
- Volume:
- 31
- Issue:
- 15
- ISSN:
- 1094-4087; OPEXFF
- Format(s):
- Medium: X Size: Article No. 24691
- Size(s):
- Article No. 24691
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Aikens, David M; Rehn, Henning; Thibault, Simon; Uhlendorf, Kristina (Ed.)Afocal telescopes are often used as foreoptics to existing imaging systems. Here, we discuss some unique aspects of designing afocal systems and detail various afocal design studies we performed using freeform optics.more » « less
-
Reimaging telescopes have an accessible exit pupil that facilitates stray light mitigation and matching to auxiliary optical systems. Freeform surfaces present the opportunity for unobscured reflective systems to be folded into geometries that are otherwise impracticable with conventional surface types. It is critical, however, to understand the limitations of the enabled folding geometries and choose the one that best balances the optical performance and mechanical requirements. Here, we used the aberration theory of freeform surfaces to determine the aberration correction potential for using freeform surfaces in reimaging three-mirror telescopes and established a hierarchy for the different folding geometries without using optimization. We found that when using freeform optics, the ideal folding geometry had 9× better wavefront performance compared to the next best geometry. Within that ideal geometry, the system using freeform optics had 39% better wavefront performance compared to a system using off-axis asphere surfaces, thus quantifying one of the advantages of freeform optics in this design space.more » « less
-
Aikens, David M; Rehn, Henning; Thibault, Simon; Uhlendorf, Kristina (Ed.)We consider the requirements for first-order pupil location control using the matrix method for both finite-conjugate systems and afocal systems at infinite imaging conjugates. We show that two-element systems allow for only limited pupil location control, while with three elements or more the first-order pupil locations can be freely and independently controlled.more » « less
-
Point spread function engineering uses specially designed phase plates placed at the exit pupil of an imaging system to reduce defocusing sensitivity. A custom phase plate is typically required for each system to enable extended depth of field imaging, so methods enabling variable extended depth of field imaging are of particular interest. In this paper, we discuss the fabrication of previously designed fixed cubic phase plates and variable phase plate pairs with quartic surface profiles and present a novel application of a point source microscope for performance characterization. Experimental measurements of through-focus point spread functions are compared with predictions to demonstrate and characterize the extended depth of field for both fixed and variable freeform phase plates.more » « less
