╗╩╣┌ÎŃ▓╩Thermoelectric Cooling Solutions

Print version

Laser Power Meters

With the significant increase in applications of lasers, instru╗╩╣┌ÎŃ▓╩ments for measuring and monitoring power and energy of the laser radiation are demanded.

Power meters and laser energy detectors are built on different principles of detection. Some types of  Photodetectors are used for this purpose.

Along with other types the thermoelectric modules are also used for the applications.

Here is a physical phenomenon that underlies the work of thermoelectric modules, namely the Seebeck effect. When one side of the thermoelectric material absorbs thermal energy and temperature difference along it appears, the electric potential difference is generated. The voltage sensitivity is determined by the Seebeck effect, which is approximately α=400 mV/°C per pair of n- and p-thermoelements. A thermoelectric module consists of many thermoelements pairs connected in series. So, thermoelectric modules are very sensitive detectors of absorbed energy.

To improve absorptive capacity and increase the sensitivity of absorption spectral band, the TEC side is covered with a special surface (black paint), making this side of a thermoelectric module similar in properties to the black body.

Power meters based on thermoelectric modules have a number of advantages:

  • Power and energy measurement of laser radiation in a wide spectral range.
  • The measurement of radiation energy and average power for large ranges of values.

For such applications it is the sensitivity of the thermoelectric module and its speed characteristics that define a number of parameters:

  • Quality of thermoelectric material.
  • The number of pairs of thermoelements to ensure the total sensitivity of thermoelectric.
  • Packing density of thermoelectric elements per unit area.
  • Thermal conductivity of the module. High thermal conductivity module increases the response speed of the absorbed radiation energy.

Single-stage modules of the company RMT of all of the series are suitable for use in sensors measuring the laser power and energy. The table identifies the key features of the preferred series.

Series

Packing density, elements/cm2

Sensitivity,V/cm2 deg.C

Minimum time constant, second

Maximum TEC size,mm2

The maximum number of pairs

1MC04

156

0.031

0.25-0.30

12.6Đů12.6

126

1MC06

100

0.020

16Đů24

140

1MD03

400

0.080

4.0Đů7.5

60

1MD04

278

0.056

9.8Đů9.8

127

1MD06

156

0.031

13Đů13

127

 

From the point of maximum practical suitability, we should to consider in the first place modules having a square top side and high density packaging elements and the number of elements (important for integral sensitivity)., as well as modules with maximum low profile (thickness) and constru╗╩╣┌ÎŃ▓╩cted with aluminum nitride ceramics.

The single-stage modules 1MD04 and 1MD06 series with more thermocouples are most preferred.

RMT can optimize or develop special stru╗╩╣┌ÎŃ▓╩ctures of thermoelectric modules to suit customer requirements. It is also possible to design special modules the necessary form and the combined modules for sensitive sensors.

All the products are manufactured in whole conformity with the standard of reliability Telcordia GR468 Core. The modules of RMT are fully compliant with RoHS đŞ REACH requirements.

To select a suitable solution and the optimal TEC for an application, the supporting Online TEC Assistance is available at RMT’s website. For detailed modeling and calculations the company RMT provides our customers by free software TEC Cad or iTECPad.

And contact RMT for a advice and assistance.