Stabilizing Laser Lines by Specified Surroundings

Maintenance-free cooling in a small space: peltier elements allow a specific cooling of sensitive components. With appropriate models the stability of diode lasers can be improved (Source: Eureca Messtechnik)

Maintenance-free cooling in a small space: peltier elements allow a specific cooling of sensitive components. With appropriate models, the stability of diode lasers can be improved (Source: Eureca Messtechnik)

Diode lasers need defined temperatures to accomplish constant emission wavelengths. Uncontrolled warming, either by thermal power loss of the laser diode itself or by the warmth of the surroundings, may lead to drifts in the emitted wavelengths or even to power changes. Although low-vibration high-power cooling compressors are available, their size often makes them unsuitable for the cooling of laser diodes.

The plate-shaped cooling elements neither need cooling agents nor complex functional setups, which makes them reliable and requires little space. The format can be selected according to the application. (Source: Eureca Messtechnik)

The plate-shaped cooling elements neither need cooling agents nor complex functional setups, which makes them reliable and requires little space. The format can be selected according to the application. (Source: Eureca Messtechnik)

Sensor expert Eureca Messtechnik develops custom cooling systems that are suitable for assembly into small and sensitive areas such as laser diode modules: peltier elements used for this are scarcely space-consuming, do not contain moving parts and furthermore neither need presser nor cooling agents, which makes them durable and low-maintenance. To ensure optimal cooling power, the elements are sized and tailored according to the specific application.

Peltier elements basically consist of differently doted bismuth telluride blocks that are soldered between ceramic plates making these parts compact and flat. The service life of these elements can be thirty years and even longer, while maintaining nearly all of their performance. The elements can be produced in various sizes and cooling performances so that there is a part for nearly every application available or can be developed easily.

A very common adjustment of the elements is the sealing of the gap between the ceramic plates with silicone, polyurethane or epoxide to protect them against moisture and to guarantee performance stability.

In addition, custom as well as standard elements can be equipped with wires and connectors to ensure an easy assembly into the laser diode modules.

Optionally Eureca also manufactures complete cooling modules. In this way, a smooth cooperation of its components and a reliable heat transfer from the laser diode to the heat sink can be accomplished. (Source: Eureca Messtechnik)

Optionally, Eureca also manufactures complete cooling modules. In this way, a smooth cooperation of its components and a reliable heat transfer from the laser diode to the heat sink can be accomplished. (Source: Eureca Messtechnik)

In order to determine the dimensions of a suitable peltier element with regards to cooling temperature, cooling power and the respective conditions of the surroundings, Eureca has developed a simulation software that describes heat flows in various configurations and conditions. This leads to a physically based selection of suitable components and reduces unnecessary trial-and-error loops that are often used for approaching a suitable solution. According to the simulated values, specific characteristics of the peltier elements are determined: A suitable element can either be selected from the broad variety of standard types or a custom development can be decided on, which can easily be started using the simulated values. The range of standard sizes is from 4.3 × 4.3 mm, which can for example be used for single sensors, up to high-performance elements with sizes up to 62 × 62 mm.

Using single elements, cooling powers up to 450 Watt and more can be achieved. For higher cooling power, parallel use of multiple elements is common practice. Moreover, multistage elements are available for low-temperature applications, which provide temperature differences between the hot and the cold side of up to above 130 Kelvin.

Eureca also determines all other components that are necessary for the smooth operation of the peltier elements, such as heat sinks, fans, if applicable, water coolings as well as heat conductive products e.g. glues, pads or pastes. To accomplish the required temperature, Eureca also selects appropriate power supplies, temperature sensors and controllers and also assembles cooling modules from prototypes or single parts, up to serial production. (Source: Eureca Messtechnik)

Link: Eureca Messtechnik GmbH, Cologne, Germany

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