Technical Notes

Fundamentals of Spatial Filtering

Technical Notes

Spatial filters provide a convenient way to remove random fluctuations from the intensity profile of a laser beam. This greatly improves resolution — which is especially critical for applications like holography and optical data processing.

Polarization Control with Optics

Technical Notes

Precise control of polarization behavior is necessary to obtain optimal performance from optical components and systems. Characteristics such as reflectivity, insertion loss, and beamsplitter ratios will be different for different polarizations.

UAV Imaging Systems

Technical Notes

When equipped with high-performance thermal imaging systems, UAVs, also known as drones, lend themselves to a wide range of defense, government, and commercial applications.

Beam Expanders

Technical Notes

Simple beam expanders are essentially telescopes which, in their most basic forms, consist of two lenses. The input beam is assumed to be collimated. The first lens must have a diameter larger than the diameter of the input beam to avoid clipping the...

Variable Laser Attenuators

Technical Notes

Variable laser attenuators consist of essentially two optical components, a half waveplate, and a polarizer with a good extinction ratio, and allow for continuous power control for linearly polarized lasers.

Focusing and Collimating

Technical Notes

As a first example, we look at a common application, the focusing of a laser beam to a small spot. The situation is shown in Figure 5. Here we have a laser beam, with radius y1 and divergence θ1 that is focused by a lens of focal length f. From the f...

Fiber Optic Basics

Tutorials

Optical fibers are circular dielectric wave-guides that can transport optical energy and information. They have a central core surrounded by a concentric cladding with slightly lower refractive index.

Gaussian Beam Optics

Technical Notes

The Gaussian has no obvious boundaries to give it a characteristic dimension like the diameter of the circular aperture, so the definition of the size of a Gaussian is somewhat arbitrary. Figure 1 shows the Gaussian intensity distribution of a typica...

Fiber Optic Coupling

Technical Notes

The problem of coupling light into an optical fiber is really two separate problems. In one case, we have the problem of coupling into multimode fibers, where the ray optics of the previous section can be used. In the other case, coupling into single...

Beam Shaping with Cylindrical Lenses

Technical Notes

Cylindrical Lenses focus or expand light in one axis only. They can be used to focus light into a thin line in optical metrology, laser scanning, spectroscopic, laser diode, acousto-optic, and optical processor applications. They can also be used to ...
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