Technical Notes

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

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

Incoherent Light Source Physics

The incoherent light sources discussed here share several characteristics that distinguish them from lasers. Incoherent light gives rise to radiation, which is emitted from the source …

Technical Notes

Radiometric Measurement

Radiometry is the measurement of energy or power in electromagnetic radiation fields or light. The average output power is the most common radiometric measurement since many light sources, …

Technical Notes

Photoreceiver Characteristics

The characteristics of such high-speed photoreceivers as well as their associated applications are the subjects of this technical note.

Technical Notes

Types of Photoreceivers

The main types of photoreceivers are those that can detect optical signals with fast temporal responses or those containing high frequency components.

Technical Notes

Laser Beam Profile Measurement

Given the different types of laser beam spatial distributions and their evolution as they propagate in free space and through optical elements, measurement of the beam profile is critical …

Technical Notes

Laser Pulse Characterization

Accurate temporal characterization of pulsed sources is as critical as accurately estimating the pulse energy and spatial and spectral profiles.

Technical Notes

Diffraction Grating Physics

A diffraction grating is essentially a multi-slit surface. It provides angular dispersion, i.e., the ability to separate wavelengths based on the angle that they emerge from the gr …

Technical Notes

Optical Transceiver Physics

OE converters typically employ photodiodes to absorb incoming photons and convert them into electrical current. Photodiodes are devices in which p-type, n-type, and intrinsic semiconductors …

Technical Notes

Introduction to FTIR Spectroscopy

An FT-IR Spectrometer is an instrument which acquires broadband NIR to FIR spectra. Unlike a dispersive instrument, i.e. grating monochromator or spectrograph, FT-IR Spectrometers collect …

Technical Notes

High Speed Detectors

There are many common parameters one considers when selecting a detector for a particular application. These include pulsewidth, bandwidth, responsivity, spectral sensitivity, noise …

Technical Notes

Information on Spectral Irradiance Data

The radiometric data shown at the end of this section was measured in our Standards Laboratory. The wavelength calibrations are based on our spectral calibration lamps. Irradiance data …

Technical Notes

Optical Detector Definitions of Characteristics

This glossary covers important terms relating to our New Focus photodetectors and photoreceivers.

Technical Notes

Optical Radiation Terminology and Units

There are many systems of units for optical radiation. In this tutorial, we try to adhere to the internationally agreed CIE system. The CIE system fits well with the SI system of units. …

Technical Notes

Optical Detection Systems

In a typical photo-research system, a detector measures the radiant intensity used to evoke photo-response in a sample or the radiant intensity produced by the sample in response to …

Technical Notes

Using Spectral Irradiance Curves

Here we describe our spectral irradiance curves. Again, we caution you on the need for testing of the final configuration particularly when the “total radiation budget” for the system, …

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