Technical Notes

Technical Notes

Fundamentals of Spatial Filtering

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 …

Technical Notes

Essentials of Laser Safety

Learn about laser classifications and the controls and protective equipment required to stay safe.

Technical Notes

Fundamentals of Laser Diode Control

To assess the quality, performance, and characteristics of laser diodes, manufacturers often perform exhaustive testing which requires electro-optical, spectral and spatial characterization …

Technical Notes

Thermopile Sensor Physics

Thermopile sensors are based on thermocouples. A thermocouple consists of two dissimilar metals connected in series. To detect radiation, one metal junction is typically blackened to …

Technical Notes

Pyroelectric Sensor Physics

A pyroelectric crystalline material has electric polarization even in the absence of an applied voltage. On heating, the material expands and produces a change in the polarization which …

Technical Notes

Photodiode Sensor Physics

A photodiode sensor consists of a semiconductor p-n junction. Light falling on the junction causes the formation of electron-hole pairs. In photovoltaic mode, the electron-hole pairs …

Technical Notes

Polarization Control with Optics

Precise control of polarization behavior is necessary to obtain optimal performance from optical components and systems. Characteristics such as reflectivity, insertion loss, and beamsplitter …

Technical Notes

UAV Imaging Systems

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.

Technical Notes

Laser Physics

A laser is a source of coherent light. It contains an optical oscillator that increases the amplitude of an optical field while maintaining its phase. This coherent amplification is …

Technical Notes

Light-Matter Interactions in Lasers

Light is generated from a laser as a result of the following process: electrons in a material move from an excited energy level to a lower-lying energy level and produce photons that …

Technical Notes

Beam Expanders

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 …

Technical Notes

Variable Laser Attenuators

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 …

Technical Notes

LED Characterization

Measurement techniques of the power, flux (equivalent to power but measured in units of lumens), and spectrum of LEDs is not very different from that of traditional light sources.

Technical Notes

Laser Beam Spatial Profiles

The irradiance distribution of a laser beam is determined by the transverse modes that exit the laser cavity. Typically, the lowest-order transverse mode (TEM00) is selected for emission …

Technical Notes

Characteristics of Laser Light

The most common laser light characteristics include: wavelength, gain bandwidth, monochromaticity, spatial and temporal profiles, collimation, output power, coherence and polarizat …

Technical Notes

Critical Laser Components

The critical components of a laser are a gain medium (acts as medium for population inversion), a pump source (serves as energy source for inverting population), and a resonator (provides …

Technical Notes

Types of Lasers

Lasers are typically identified by their gain medium and are often classified by the radiating species that give rise to stimulated emission.

Technical Notes

Methods for Pulsed-Laser Operation

It is often desirable to operate lasers in a pulsed mode since this can significantly increase the peak output power.

Technical Notes

Laser Spectral Tunability

The first way to perform laser wavelength tuning uses a wavelength-selective element to choose a specific portion under a gain bandwidth to lase. The second method of wavelength tuning …

Technical Notes

Laser Diode and LED Physics

Laser diodes possess several unique attributes compared to other types of lasers. They are very small compared to other classes of lasers, can operate very efficiently with relatively …

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