Photonics Handbook

Diffraction gratings are optical components with a periodic structure that separate light into beams traveling in predictable directions based on their wavelength. The grating acts as the dispersive...

Except for direct illumination from the sun, laser, or other light source, everything we see or detect is ultimately scattered light. Light can be scattered or rescattered during its propagation to...

Developed in the early 1990s, the silicon photomultiplier (SiPM) is a solid-state photodetector whose sensitivity to light rivals that of a photomultiplier tube (PMT) in a regime where a few hundred...

Electrical engineers are very familiar with the effects of shot noise, thermal noise, flicker noise and crosstalk, and recognize how these effects can reduce the signal-to-noise ratio (SNR) in their...

There are three fundamental properties of light: intensity, wavelength, and polarization. Almost all cameras today are designed for monochrome or color imaging. A monochrome camera is used to measure...

Technological advances have resulted in new, higher-quality sensors that enable machine vision cameras to deliver greater features and functionality at a lower cost than ever before. These factors...

Many common spectroscopic measurements require the coordinated operation of a detection instrument and light source, as well as data acquisition and processing. Integration of individual components...

When evaluating the surface of a component, surface roughness can be assessed by eye or by rubbing it with a fingertip. Common expressions include “shiny,” “lusterless and...

Given the pace at which technology advances, there always seems to be a learning curve. With the abundance of consumer electronics available, there typically is no right or wrong way to use these...

Optical fibers are made from either glass or plastic. Most are roughly the diameter of a human hair, and they may be many miles long. Light is transmitted along the center of the fiber from one end...

Light is a versatile tool for investigating physical and chemical processes in nature. Any specific system being analyzed may, through the light it emits or reflects, communicate information about...

When purchasing an industrial laser system, the astute buyer will look for a Class 1 laser product — a system where the laser beam hazard is completely enclosed and there is no potential laser...

Laser development for the microscopy market continues to be driven by key trends in applications, which currently include superresolution techniques, multiphoton applications in optogenetics and...

Any number of medical, industrial, and analytical applications requires the detection of light. Chemiluminescence, bioluminescence, fluorescence, and atomic absorption are just a few, and all require...

In their earliest forms, UV bandpass filters that were optimized for wavelengths less than 400 nm, such as the Schott UG or the Hoya U-series, were constructed of absorbing compounds in glass. Such...

An integrating sphere’s function is to spatially integrate radiant flux (light). However, before one can optimize a sphere design for a particular application, it is important to understand how...

What are thin-film coatings? The purpose of any optical thin-film coating is to modify the transmittance and reflectance properties of the substrate material to which they are applied. Most coatings...

The first high-reflectance mirror coatings for the UV and vacuum UV (VUV) were of the Al + MgF2 type produced in the late 1950s. Coatings of this design are still used today for multigas cavity...

Over 60 years have passed since the first demonstration of a laser in 1960. After the initial spark of interest, lasers were for a while categorized as “a solution waiting for a problem,”...

With a specific gravity of 1.85 g/cm3, beryllium is the lightest metal that is workable. It is 45 percent lighter than aluminum and approximately five times as stiff. Its stiffness to weight ratio...

Optical coatings are deposited as thin-film multilayers of a variety of materials using specific deposition techniques. Coatings are applied to optical components that are intended for use at...

Photonics Rules of Thumb Scientists and engineers tend to want to answer simple relational questions with a blackboard covered with equations, even when questioners just want a rough estimate to...

An optical time-domain reflectometer sends short pulses of light into a fiber and measures its reflections as a function of time. The delay of these reflections to the detector as well as their...

The basic setup in laser perforation includes a pulsed laser, a lens and either a moving mirror, a rotating web or both. Each laser pulse creates a hole in the material. During the blank time in...

Charged-injection device imagers are metal-oxide semiconductor (MOS) detectors that can be fabricated using PMOS, NMOS and CMOS integrated circuit technology, and may be configured as a...

That portion of the spectrum that the eye can see — and its rainbow of colors — is rather small, covering approximately 360 to 830 nm. What colors we perceive depends on wavelength, while...

The common polycrystalline materials used for optical thin-film materials do not satisfy the requirements of telecommunications because of the instabilities caused by moisture absorption in their...

Reflected-ultraviolet imaging is a rather mysterious area of the imaging field. There is relatively little actual UV imagery to be found on the Internet or in the literature compared to near-infrared...

Infrared system design is not, like some circuit design, a synthetic process. One cannot start by stating the problem and proceeding in an orderly fashion to a final solution. Rather, we guess a...

DATA TABLES: OPTICAL THIN-FILM MATERIALS Identification Physical Parameters Material Name Material Formula Transparent Region(µm) (see note a) Index at Wavelength...

A lens collects light from a point on an object and focuses it to a corresponding conjugate point on an image. Under most conditions, the lens fails at this task because of some error in the...

Like other CTDs, the CID imager uses hundreds of thousands (up to 4 million) pixel elements to capture optical images, and converts the light into an electronic charge which may be displayed on a...

Designing devices that incorporate ultrathin films is an important means of enhancing yields. However, characterizing ultrathin films provides a challenge for mainstream metrology tools such as...

Optics can be contaminated in many ways. Contamination can be kept to a minimum by returning the optics to their case after use or by covering the optics for protection from the outside environment....

There is a growing market for imaging systems that provides an immediate, slow-motion view of a process that allows one to see events that happen too quickly for the human eye to perceive or...

Just as an electronic connector provides a pluggable connection between electronic circuits, a fiber optic connector provides an optical one. The goal is joining a fiber to a transmitter, receiver or...

Controlling and minimizing heat output is desirable in most lighting applications. For example, conventional incandescent light sources are very inefficient with only a small portion of the...

Applications facilitated by tunable lasers fall into two categories: situations in which one or more discrete wavelengths are not available from any single- or multiline fixed-wavelength laser, or...

The market for flat panel displays (FPDs) has undergone tremendous growth, driven mostly by increased demand for televisions, cell phones, computers, digital cameras and MP3 players. Similarly,...

All optical spectrometry techniques rely on the measurement of radiant power. The configuration of the instrument varies based on the measurement technique: absorption, emission, luminescence, or...

An optical coating engineer is frequently confronted with a difficult specification for a coating. Often the difficulty in the specification results from the particular form of the optical system. If...

Optics today needs alchemy, and the forces that motivate microchip technology are a key reason why. Today, light can transmit and process digital information as well as electricity can — in...

When physical structures get very small — on the order of molecular or atomic sizes with one or more dimensions on the nanoscale — their behavior and interactions with energy, including...

Reading and writing systems for polygonal scanners differ in the use of the scanner. However, many performance characteristics are similar for both. In writing applications, a light source, usually a...

Plate beamsplitters Plate beamsplitters consist of a thin plate of optical crown glass with a different type of coating deposited on each side. The first surface is coated with an all-dielectric...

Some efforts in global optimization research for optical design center around probabilistic methods such as global search. While promising for small problems with few variables, these methods...

Lenses come in a variety of shapes, sizes and materials. They can be made of a single piece of glass or have multiple elements; their surfaces can be spherical, aspheric or cylindrical; they can be...

For any discussion of laser beam diagnostics, it is first necessary to define some terms that characterize beam properties. Broad definitions can include measurements of laser energy or power,...

In the beginning, automated inspection focused on the camera and optics, the algorithms, the interface hardware and the processor. Only rarely was attention paid to the lighting system or lighting...

NSOM is suitable for studies on the mesoscopic scale (several tens to hundreds of molecular dimensions). It has become an important tool in research and applications of semiconductors, organic layers...