Optics 101

Xenon Arc Lamps - White Light for Photometry and Microscopy

Topics Covered

Introduction
Operation and Spectral Output
Construction
Applications
References

Introduction

A xenon arc lamp is a specialized gas discharge lamp that emits light when electricity is passed through ionized xenon gas that is maintained at high pressure. Xenon gas is ionized by electric current. These lamps are continuous sources of light of highest luminance and radiance.

Xenon arc lamps are denoted by XBO where X stands for xenon, B stands for luminescence and O for unforced cooling. Xenon gas is maintained at high pressure and hence emits light of wavelengths that are evenly distributed over fluorophores. This article will elaborate on the working, construction and applications of xenon arc lamps.

Operation and Spectral Output

Xenon gas is maintained at high pressure inside an arc tube. The arc tube is fitted with two electrodes through which high voltage is passed. At high voltages, xenon gas is ionized and emits bright white light.

Xenon arc lamps are of two types: one is pure xenon gas and another is xenon and mercury. Both the lamps operate at very high temperatures, hence require a cooling arrangement. Xenon lamps emit white light that closely resembles sunlight.

Construction

The xenon lamp consists of an ellipsoidal envelope made of fused silica quartz, as it is capable of withstanding very high temperatures. The electrodes are made of forged tungsten or tungsten alloys. The filling gas either consists of pure xenon or a combination of xenon and mercury.

Applications

Some of the areas of application of the xenon arc lamps are mentioned below:

  • High precision photometry
  • Quantitative fluorescence microscopy
  • Automotive headlamps.

References

 

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