Five Cooling Temperature Grades for SWIR Cameras

Ⅰ、The Importance of Cooling for SWIR Cameras

Signal-to-Noise Ratio (SNR) is a critical parameter that characterizes the imaging performance of SWIR cameras.

SWIR cameras use InGaAs as the sensor material, with a typical dark current of 18.75 ke⁻/pixel/s. In comparison, silicon-based detectors at room temperature exhibit a dark current of only about 40 e⁻/pixel/s. Therefore, the SNR of SWIR cameras is largely dominated by the dark current level. Cooling the sensor chip can effectively suppress dark current, so the cooling temperature of a SWIR camera can serve as a reference indicator for its maximum SNR. Based on this, I have divided SWIR camera cooling temperatures into five levels: room temperature (20°C), –10°C, –20°C, –50°C, and –100°C, and for each level, representative products are listed.

Ⅱ、Cooling Temperature Grades

2.1、20°C Room Temperature (Uncooled)

The detector temperature varies with the ambient temperature, and there is no built-in cooling module. This type of camera offers the smallest size, lowest power consumption, lowest cost, and simplest integration; however, it has the highest dark current, which varies significantly with temperature. It is only suitable for basic industrial scenarios with sufficient lighting and high-speed production lines, and cannot meet the requirements of low-light and precision inspection.

Representative Products:

2.2、-10°C Mild Cooling

It employs single-stage TEC cooling technology, which can stably reduce the detector temperature to –10°C. The –10°C cooling moderately suppresses dark current, while the camera maintains a simple structure and low power consumption, balancing cost and low-noise performance. It is widely used in food sorting, agricultural product sorting, and most industrial vision applications.

Representative Products:

2.3、-20°C Standard Cooling

-20°C is currently the general standard cooling level in the SWIR camera market. Leveraging mature two-stage TEC cooling technology, it provides stable temperature control and achieves an optimal balance among device size, power consumption, and imaging performance. It is suitable for the vast majority of semiconductor inspection, laser analysis, hyperspectral imaging, and laboratory low-light imaging applications.

Representative Products:

2.4、-50°C Deep Cooling

It features a vacuum-sealed chamber and a multi-stage TEC deep-cooling architecture, capable of stably maintaining an ultra-low operating temperature of –50°C. The detector dark current is extremely suppressed, supporting second-level long exposures and enabling precise capture of weak optical signals. This cooling tier is the core choice for high-end scientific research applications and is widely used in fluorescence imaging, Raman spectroscopy, precision microscopy, biological tissue imaging, and other high-precision fields.

Representative Products:

2.5、-100°C Ultra-Deep Cooling

This type of camera employs liquid nitrogen or Stirling mechanical refrigeration technology, which can reduce the detector temperature to –100°C or lower, achieving the industry’s ultimate level of noise reduction. It enables extremely weak photon-counting imaging, with exposure times of up to several hours. This class of equipment offers top-tier imaging precision, but is large in size, high in power consumption, and costly to maintain. It is suitable for scenarios such as astronomical observation, cutting-edge precision spectroscopic measurement, and ultra-long-exposure spectral analysis.

Representative Products: