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What Optics Do You Need for Your Lidar Development?
These days almost every optics magazine seems to have articles covering some aspect of lidar systems. Lidar, or LiDAR if you prefer, is the acronym for Light Detection And Ranging and sees applications in fields such as topographic land mapping, aerial inspection, agriculture and defense. The big growth area we’ve seen in recent years has…
Read MoreWhen is a Fresnel Lens not a Fresnel Lens?
It’s well known, to those who know it well, that diffractive optics and refractive optics suffer chromatic shift but that is opposite in sense. This is illustrated nicely by comparing a blazed grating with a Fresnel lens as shown below. Bear in mind these figures have more artistic license than a Pink Floyd album cover! …
Read MoreEtendue of a Fly’s Eye Illuminator
In the first blog article I introduced the subject of étendue and its importance in illumination systems. The example used was simple optical relay, but many systems utilize fly’s eye arrays to provide homogenous illumination. What is the impact of splitting a beam into smaller beamlets on the étendue? Consider this system….. On the left…
Read MoreFabless Manufacturing Applied to Optics
Fabless manufacturing is common nowadays in the semiconductor industry with the likes of Qualcomm, NVIDIA and Apple being well known proponents. These are companies who concentrate on design and marketing of their products but don’t take any part in the fabrication of the product. Fabless manufacturing started in the 80s in Silicon Valley (a relative…
Read MoreHow would you like your distortion, rectilinear or curvilinear?
If you want to commission a custom-designed lens you need to define your specification. There are straightforward parameters, like field of view and resolution but a tricky one to specify is distortion. There are two main forms of distortion, rectilinear and curvilinear. Rectilinear is what most people are more familiar with. It is based on…
Read MoreWhether it’s hot or cold, stay focused! What’s involved in lens athermalization.
A huge range of commercial-off-the-shelf lenses are readily available from many catalog optics suppliers. However, sometimes what you want is not available and you just need a custom design. One of the features often required in custom lenses is that they operate over a wide temperature range without manual or motorized adjustment. You find such…
Read MoreCamera Sensor: WTF is the MTF?
One of Selene Development’s key product areas is custom lenses for specialist camera systems for applications ranging from autonomous vehicles to space to life science microscopy. The resolution of our lenses is usually defined by MTF and we design and build lenses to an MTF specification. But the lens is only part of the system…
Read MoreImage Relay Beam Expander
Surely virtually everyone who has worked with lasers has used a beam expander. There are two basic types, as shown below (you can also use mirrors or prisms): Sometimes there is a special case when you want the expander to do two things: expand the beam and also provide a relay between conjugate planes, ie…
Read MoreThe Lagrange Invariant Strikes Again!!
Imagine this. You’ve been asked if you can optimize the design of an illuminator to improve the efficiency, that is, get more light on to a detector. Increasingly higher power LEDs have been tried but to no avail. Your immediate reaction is “ah, the Lagrange Invariant strikes again!!” Much of the optics world has people…
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