SOURCE: AFI
Scientists at the Indian Institute of Science (IISc) have made a significant breakthrough in infrared imaging technology. They’ve created a device that can “up-convert” invisible infrared light to a visible range, allowing us to see it directly.
The human eye can only see a specific range of light frequencies, known as the visible spectrum. Infrared light falls outside this range, with even lower frequencies than red light. While invisible, infrared has various applications in fields like astronomy, defense, and night vision.
Current infrared imaging relies on bulky and often export-restricted sensors that detect heat signatures. These are not ideal due to their limitations and the desire for indigenous solutions.
The IISc team’s solution involves a unique “non-linear optical mirror stack” made from a 2D material called gallium selenide. This innovative design allows them to achieve up-conversion.
The device functions by directing an infrared signal along with a pump beam onto the mirror stack. The special properties of the material cause the frequencies to mix, resulting in an output beam with a higher (up-converted) frequency. This up-converted light falls within the visible spectrum and can be detected by regular silicon-based cameras.
Advantages of the IISc Method:
- Preserves Information: The up-conversion process is coherent, meaning the information encoded in the original infrared signal is retained in the visible output.
- Compact and Cost-Effective: The use of a thin layer of gallium selenide (just 45 nm) makes the device smaller and potentially cheaper than traditional methods that use large crystals.
- Performance and Efficiency: Despite its compact size, the device’s performance is comparable to current state-of-the-art up-conversion systems.