Laser Power Measurement

Laser Power monitoring is a direct and trivial application for any light detector. However there is one major difference between detectors used in power meters, and those used in power monitoring; detectors for power monitoring are not calibrated to a specific power level.

In power monitoring applications a detector is used to produce a feedback loop between the output of a laser and the electronics used to control it, producing a stabilized output power. Although this might sound simple, care has to be taken so a detector is not over saturated and the laser is within the detectors range of linearity. This is why beamsplitters or side reflections are used to only observe a small fraction of the laser light.

Build Laser Power Meters

with the right Detector

In most power monitoring applications the smallest photodiode will be more than enough to do the job; however, if you are looking to record the absolute power - even in arbitrary units - then larger area photodiodes are recommended.

Care also has to be taken to select the right spectral range, and effects of temperature are taken into account.

InGaAs or Silicon?

For lasers in the 900 – 1000 nm region silicon is still a popular choice of detector for power monitoring despite the fact that its responsivity is heavily temperature dependent in this spectral range.

InGaAs on the other hand has a far better temperature coefficient over this spectral band, with our IG17 series having a temperature coefficient of <0.1%/K. With the same coefficient becoming an entire order of magnitude less with our IG22 chemistry.

Pyroelectric

A high speed version with integrated OpAmp can be a sound option for applications up to a few kHz in cases where semiconductor based detectors are unsuitable.

Product Selection

for different needs

Detectors to build Power Meters

Pyroelectric crystals generate positive and negative charge carriers simultaneously on opposing sides. The LD21xx series is the first series in which both crystal sides are amplified separately.

IR photodiodes with an emphasis on quantum efficiency: LASER COMPONENTS develops and manufactures photodiodes in the spectral range of up to 2600 nm.

DLaTGS detectors exhibit the most effective pyroelectric effect known. Their major application is FTIR.

DLaTGS = Deuterated Lanthanum α Alanine doped TriGlycine Sulphate

Laser Optics for Laser Beam Diagnostics

DIAGNOSTIC BEAM SPLITTERS FOR PROCESS MONITORING

Dichroic mirrors separate or combine two or more beams of different wavelengths in the desired ratio and enable process monitoring on the operating level in several wavelength ranges, as well as beam diagnostics. Their complex design enables multiple transmission and reflection ranges.

FOR SPLITTING INTO ONE OR MORE DEFINED PARTIAL BEAMS.

When working with lasers, it is often necessary to split a laser beam into two or more defined partial beams. There are a variety of beam splitters for these applications, with different advantages and disadvantages. Dielectrically coated beam splitters have a high laser damage threshold.