Guillermo Biot

Novel fast catadioptric objective with wide field of view

Using the Simultaneous Multiple Surface method in 2D (SMS2D), we present a fast catadioptric objective with a wide field of view (125°×96°) designed for a microbolometer detector with 640×480 pixels and 25 microns pixel pitch Keywords: Infrared lens design, thermal imaging, Schwarzschild configuration, SMS2D, wide field of view, driving cameras, panoramic systems

SMS-based optimization strategy for ultra-compact SWIR telephoto lens design.

A new optical design strategy for rotational aspheres using very few parameters is presented. It consists of using the SMS method to design the aspheres embedded in a system with additional simpler surfaces (such as spheres, parabolas or other conics) and optimizing the free-parameters. Although the SMS surfaces are designed using only meridian rays, skew rays have proven to be well controlled within the optimization. In the end, the SMS surfaces are expanded using Forbes series and then a second optimization process is carried out with these SMS surfaces as a starting point. The method has been applied to a telephoto lens design in the SWIR band, achieving ultra-compact designs with an excellent performance.

Ultra-High Efficiency, High-Concentration PV System Based On Spectral Division Between GaInP/GaInAs/Ge And BPC Silicon Cells

A novel HCPV nonimaging concentrator concept with high concentration (>500×) is presented. It uses the combination of a commercial concentration GaInP/GaInAs/Ge 3J cell and a concentration Back‐Point‐Contact (BPC) concentration silicon cell for efficient spectral utilization, and external confinement techniques for recovering the 3J cells reflection. The primary optical element (POE) is a flat Fresnel lens and the secondary optical element (SOE) is a free‐form RXI‐type concentrator with a band‐pass filter embedded it, both POE and SOE performing Kohler integration to produce light homogenization. The band‐pass filter sends the IR photons in the 900–1200 nm band to the silicon cell. Computer simulations predict that four‐terminal terminal designs could achieve ∼46% added cell efficiencies using commercial 39% 3J and 26% Si cells. A first proof‐of concept receiver prototype has been manufactured using a simpler optical architecture (with a lower concentration, ∼100× and lower simulated added efficiency), a...

Advances in the SMS design method for imaging optics

In this work, two SMS algorithms are presented for an objective design with different selected ray-bundles: three meridian ray-bundles (3M) and one meridian and two skew ray-bundles (1M-2S), the latter from pin hole point of view, provides a better sampling of the phase space. Results obtained with different algorithms will be compared.

Progress in the SMS design method for imaging optics

In this work, two SMS algorithms are presented for an objective design with different selected ray-bundles: three meridian ray-bundles (3M) and one meridian and two skew ray-bundles (1M-2S), the latter from pin hole point of view, provides a better sampling of the phase space. Results obtained with different algorithms will be compared.

Ultracompact SWIR telephoto lens design with SMS method

In this work, we propose two new optical structures, using the Simultaneous Multiple Surfaces (SMS) method, comprised of 2 reflecting surfaces and 2 refracting surfaces, 800mm focal length, f/8 (aperture diameter 100 mm) and 1.18° diagonal field of view in the SWIR band. The lens surfaces are rotational symmetric and calculated to have good control of non-paraxial rays. We have achieved designs with excellent performance, and with total system length of less than 60 mm.

Solid Catadioptric telephoto lens design with SMS method

Two new optical structures are designed using the Simultaneous Multiple Surfaces (SMS) method, comprised of 2 reflecting surfaces and 2 refracting surfaces, 800mm focal length, f/8 (aperture diameter 100 mm) and 1.180 diagonal field of view in the SWIR band. The lens surfaces are rotational symmetric and calculated to have good control of non-paraxial rays. We have achieved designs with excellent performance, and with total system length of less than 60 mm.

Metal-less V-groove RXI collimator

A metal-less RXI collimator has been designed using the Simultaneous multiple surface method (SMS). The collimator is completely made of plastic (PMMA) and does not include any mirrored surface, unlike to the convectional RXI collimators, whose back surface is metalized to provide a specular reflection. The back surface of the V-groove RXI is designed as a grooved surface providing two TIR reflections for all rays impinging on it. The main advantage of the presented design is lower manufacturing cost since there is no need for the expensive process of metalization. Also, unlike to the conventional RXI collimators this design performs good colour mixing. The experimental measurements of the first prototype are presented.

Design of a compact objective for SWIR applications

Lately the short-wave infrared (SWIR) has become very important due to the recent appearance on the market of the small detectors with a large focal plane array. Military applications for SWIR cameras include handheld and airborne systems with long range detection requirements, but where volume and weight restrictions must be considered. In this paper we present three different designs of telephoto objectives that have been designed according to three different methods. Firstly the conventional method where the starting point of the design is an existing design. Secondly we will face design starting from the design of an aplanatic system. And finally the simultaneous multiple surfaces (SMS) method, where the starting point is the input wavefronts that we choose. The designs are compared in terms of optical performance, volume, weight and manufacturability. Because the objectives have been designed for the SWIR waveband, the color correction has important implications in the choice of glass that will be discussed in detail.

Imaging system applications of multichannel configuration

While multichannel configurations are well established for non-imaging applications, they have not been used yet for imaging applications. In this paper we present for the first time some of multichannel designs for imaging systems. The multichannel comprises discontinuous optical sections which are called channels. The phase-space representation of the bundle of rays going from the object to the image is discontinuous between channels. This phase-space ray-bundle flow is divided in as many paths as channels there are but it is a single wavefront both at the source and the target. Typically, these multichannel systems are at least formed by three optical surfaces: two of them have discontinuities (either in the shape or in the shape derivative) while the last is a smooth one. Optical surfaces discontinuities cause at the phase space the wave front split in separate paths. The number of discontinuities is the same in the two first surfaces: Each channel is defined by the smooth surfaces in between discontinuities, so the surfaces forming each separate channel are all smooth. Aplanatic multichannel designs are also shown and used to explain the design procedure.