Applied Industrial Optics

26 July 2021 – 30 July 2021
Optica Virtual Event - Eastern Daylight/Summer Time (UTC - 04:00)

I'm Free, Free-Forming (Th2A)

Presider: Jess Ford, Weatherford International Ltd

I'm Free, Free-Forming (Th2A)

Presider: Jess Ford, Weatherford International Ltd
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10:30 - 11:00
(UTC - 04:00)

Tunable Lenses for Wavefront Correction (Th2A.1)
Presenter: Frieder Mugele, Universiteit Twente

In the absence of external forces, liquid spontaneously assume a spherical cap shape if their edge is either free to move or pinned along the rim of a circular aperture. The curvature of the surface and hence refractive power of the resulting lens are governed by the pressure drop across the liquid surface. By controlling either the pressure drop or the diameter of the aperture (e.g. by tuning the contact angle of using electrowetting), spherical liquid lenses of variable focal length can be realized. Non-spherical tunable drop shapes can either be achieved indirectly by applying non-symmetric boundary conditions along the edge of the droplets or directly by applying additional electrical forces that distort the liquid surface and in a controlled manner. I will present an overview of developments based on the latter approach. By applying variable voltages to segmented electrodes, the distribution of the electric field can be controlled. The equilibrium between the local electric stresses and the capillary pressure across the liquid surface gives rise to surface shapes that allow to vary the strength of low order aberrations (spherical, cylinder, coma) over a wide range, as evidenced by numerical simulations in combination with wavefront measurements using a Shack-Hartmann sensor. Optimization of electrode geometry and careful control of liquid-liquid interfacial tensions provide a potential for flexible aberration correction in various applications.

Authors:Frieder Mugele, Universiteit Twente

10:30 - 11:00
(UTC - 04:00)

Tunable Lenses for Wavefront Correction (Th2A.1)
Presenter: Frieder Mugele, Universiteit Twente

In the absence of external forces, liquid spontaneously assume a spherical cap shape if their edge is either free to move or pinned along the rim of a circular aperture. The curvature of the surface and hence refractive power of the resulting lens are governed by the pressure drop across the liquid surface. By controlling either the pressure drop or the diameter of the aperture (e.g. by tuning the contact angle of using electrowetting), spherical liquid lenses of variable focal length can be realized. Non-spherical tunable drop shapes can either be achieved indirectly by applying non-symmetric boundary conditions along the edge of the droplets or directly by applying additional electrical forces that distort the liquid surface and in a controlled manner. I will present an overview of developments based on the latter approach. By applying variable voltages to segmented electrodes, the distribution of the electric field can be controlled. The equilibrium between the local electric stresses and the capillary pressure across the liquid surface gives rise to surface shapes that allow to vary the strength of low order aberrations (spherical, cylinder, coma) over a wide range, as evidenced by numerical simulations in combination with wavefront measurements using a Shack-Hartmann sensor. Optimization of electrode geometry and careful control of liquid-liquid interfacial tensions provide a potential for flexible aberration correction in various applications.

Authors:Frieder Mugele, Universiteit Twente

11:00 - 11:30
(UTC - 04:00)

Addressing Total Error for Freeform Optics Ranging From Alignment to Mid-Spatial Frequency (MSF) Errors (Th2A.2)
Presenter: Jessica DeGroote Nelson, Optimax Systems Inc

Traditional optical shapes such as spheres, cylinders, and prisms are easily measured using interferometry and the specifications used to define their surface irregularity/form and geometry, such as wedge (edge thickness difference) and center thickness (CT), are straightforward and well-defined. Wedge and center thickness are very useful for understanding the position of the optical surfaces of a lens relative to each other, which can help predict the performance of the optical system. However, wedge and center thickness cannot be used to define the relationship of optical surfaces on parts with little, or no, symmetry. Freeform optics are difficult to define using traditional optical specifications like these due to the potential non-symmetry and non-uniform thickness, this difficulty forces us to find a new methods for defining the relationship of the optical surfaces. The freeform manufacturing process requires control of both the surface form and the surface location simultaneously. The combination of both surface location, surface form and mid-spatial frequency (MSF) error is referred to as total error. This presentation will explore the advantages of fabricating with the total error specified on freeform optics and how it can aid in the manufacture, measurement and assembly of freeform optical systems.

Authors:Jessica DeGroote Nelson, Optimax Systems Inc

11:00 - 11:30
(UTC - 04:00)

Addressing Total Error for Freeform Optics Ranging From Alignment to Mid-Spatial Frequency (MSF) Errors (Th2A.2)
Presenter: Jessica DeGroote Nelson, Optimax Systems Inc

Traditional optical shapes such as spheres, cylinders, and prisms are easily measured using interferometry and the specifications used to define their surface irregularity/form and geometry, such as wedge (edge thickness difference) and center thickness (CT), are straightforward and well-defined. Wedge and center thickness are very useful for understanding the position of the optical surfaces of a lens relative to each other, which can help predict the performance of the optical system. However, wedge and center thickness cannot be used to define the relationship of optical surfaces on parts with little, or no, symmetry. Freeform optics are difficult to define using traditional optical specifications like these due to the potential non-symmetry and non-uniform thickness, this difficulty forces us to find a new methods for defining the relationship of the optical surfaces. The freeform manufacturing process requires control of both the surface form and the surface location simultaneously. The combination of both surface location, surface form and mid-spatial frequency (MSF) error is referred to as total error. This presentation will explore the advantages of fabricating with the total error specified on freeform optics and how it can aid in the manufacture, measurement and assembly of freeform optical systems.

Authors:Jessica DeGroote Nelson, Optimax Systems Inc

11:30 - 11:45
(UTC - 04:00)

(Withdrawn) Fabrication of Thin Bent Crystal Optics (Th2A.3)
Presenter: Candace Lynch, Inrad Optics

We report on the fabrication of thin crystals (quartz, Ge, Si) which are mounted to curved backings without the use of adhesive. These optics have applications in x-ray imaging and spectroscopy.

Authors:Candace Lynch, Inrad Optics / Thomas Caughey, Inrad Optics / Jeff Baer, Inrad Optics

11:30 - 11:45
(UTC - 04:00)

(Withdrawn) Fabrication of Thin Bent Crystal Optics (Th2A.3)
Presenter: Candace Lynch, Inrad Optics

We report on the fabrication of thin crystals (quartz, Ge, Si) which are mounted to curved backings without the use of adhesive. These optics have applications in x-ray imaging and spectroscopy.

Authors:Candace Lynch, Inrad Optics / Thomas Caughey, Inrad Optics / Jeff Baer, Inrad Optics